The first few weird numbers are 70, 836, 4030, 5830, 7192, 7912, 9272, 10430, ... (OEIS A006037). An infinite number of weird numbers are known to exist, and the sequence of weird numbers has positive Schnirelmann density.
Weird numbers are natural numbers that are abundant but not semiperfect. For example, 70 is the lowest weird number, because its set of proper divisors {1,2,5,7,10,14,35} sum to 74, but no subset of its set of proper divisors sum to the number 70, and 70 is the smallest number to meet such conditions.
perfect number, a positive integer that is equal to the sum of its proper divisors. The smallest perfect number is 6, which is the sum of 1, 2, and 3. Other perfect numbers are 28, 496, and 8,128. The discovery of such numbers is lost in prehistory.
One (1) is the first natural number, followed by two. It represents a single item.
Solution: The proper factors of 28 are 1, 2, 4, 7, and 14. The sum of these proper factors is 28. According to the definition of perfect numbers, 28 is a perfect number.
The reason 2096128 isn't a perfect number is because that part in parentheses, 211 - 1 (which is 2047), isn't itself prime! 2047 can be factored: 23 * 89, and therefore it isn't prime. Because of this, the number 2096128, or 210 * (211 - 1), isn't a perfect number, either!
The mystery is this: first, take any three digit number, where the first and last digits differ by two or more and reverse the number to produce a new one. Then subtract the smaller from the larger producing another new number. If you reverse this number and this time add the two, the result will always be 1089.
Therefore, the number 14 in words is Fourteen.
Answer: Now note the natural numbers, which are from 1-to 100. According to arithmetic progression, natural numbers can be written down as 1, 2, 3, 4, 5, 6, 7, and 8 to 100. Basically, the sum of the first 100 natural numbers is equal to 5050.
Eight (八, hachi, ya) is also considered a lucky number in Japan, but the reason is different from that in Chinese culture. Eight gives an idea of growing prosperous, because the letter (八) broadens gradually.
8 2 14 6 11 ? 14 6 18 12. Answer in short. There the missing number is 9.
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therefore, 18 is the wrong number is the sequence .
What are the Perfect Numbers? Definition: A Perfect Number N is defined as any positive integer where the sum of its divisors minus the number itself equals the number. The first few of these, already known to the ancient Greeks, are 6, 28, 496, and 8128.
You can find a lot of 'happy numbers' such as: 310, 70, 86, 130, 7, 5555, 1212, 13, 1000 and other numbers which are variations of these, e.g. swapping the numbers the other way around (13, 31) and adding zeros onto the end of numbers (31, 310).
The first few happy numbers are 1, 7, 10, 13, 19, 23, 28, 31, 32, 44, 49, 68, 70, 79, 82, 86, 91, 94, 97, 100, ... (OEIS A007770). These are also the numbers whose 2-recurring digital invariant sequences have period 1.
The number 6174 is known as Kaprekar's constant after the Indian mathematician D. R. Kaprekar.
Therefore, the sum of the first fifty natural numbers is 1275.
The correct spelling of the number 40 is forty. In modern times, fourty is incorrect, although in the past this was likely the original spelling. Nowadays, forty is the accepted spelling and fourty is considered a mistake.
In related facts, the number 14 keeps the u: it's written as fourteen. But fortieth correlates to forty, so it too goes without a u. There is no good explanation for why forty lacks a u that its near-relation four has. Forty simply is, as American English Spelling author D.W.
The reason that the result of a division by zero is undefined is the fact that any attempt at a definition leads to a contradiction. a=r*b. r*0=a. (1) But r*0=0 for all numbers r, and so unless a=0 there is no solution of equation (1).
142857, the six repeating digits of 17 (0. 142857), is the best-known cyclic number in base 10. If it is multiplied by 2, 3, 4, 5, or 6, the answer will be a cyclic permutation of itself, and will correspond to the repeating digits of 27, 37, 47, 57, or 67 respectively.