A074751 Numbers k such that the sum of the anti-divisors of k = sum of proper divisors (or aliquot parts) of k.

1, 4, 44, 260, 1350, 6284, 6954, 13364, 273366, 333546, 466614, 4659934050

Offset: 1

Author

Jason Earls, Sep 06 2002

Keywords

• nonn
• more

Comments

Integers k such that A066417(k) = A001065(k)

a(13) > 10^10. - Hiroaki Yamanouchi, Mar 18 2015

Crossrefs

Cf. A001065, A066417, A066272.

Programs

PARI

spd(n) = if( n==0, 0, sigma(n) - n); \\ A001065
sad(n) = my(k); if(n>1, k=valuation(n, 2); sigma(2*n+1)+sigma(2*n-1)+sigma(n/2^k)*2^(k+1)-6*n-2, 0); \\ A066417
isok(k) = sad(k) == spd(k); \\ Michel Marcus, Mar 30 2025

Extensions

a(12) from Hiroaki Yamanouchi, Mar 18 2015