cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A242484 Numbers n such that antisigma(n) mod n = 0, where antisigma(n) = A024816(n) = sum of numbers less than n which do not divide n.

Original entry on oeis.org

1, 2, 24, 4320, 4680, 26208, 8910720, 17428320, 20427264, 91963648, 197064960, 8583644160, 10200236032, 21857648640, 57575890944, 57629644800, 206166804480, 17116004505600, 1416963251404800, 15338300494970880
Offset: 1

Views

Author

Jaroslav Krizek, May 16 2014

Keywords

Comments

Numbers n such that antisigma(n) mod n = A229110(n) = 0.
If there are any odd multiply-perfect numbers, they are members of this sequence.
If there is no odd multiply-perfect number, then a(n) = A159907(n-1) for n >= 2.

Examples

			24 is in sequence because antisigma(24) mod 24 = 240 mod 24 = 0.
		

Crossrefs

Programs

  • Magma
    [n: n in [1..1000000] | 0 eq ((n*(n+1))div 2 - SumOfDivisors(n)) mod n];