A139229 First differences of perfect numbers A000396, divided by 2.

11, 234, 3816, 16771104, 4278159360, 64424411136, 1152921435350630400, 1329227995784915871174424803906945024, 95780971304118052318168693257235946738152352797163520

Offset

1,1

Links

Paolo Xausa, Table of n, a(n) for n = 1..14

Formula

a(n) = A139228(n)/2.

Mathematica

Differences[Select[Range[10000], DivisorSigma[1, #] == 2# &]]/2 (* Alonso del Arte, Mar 05 2020 *)
Differences[PerfectNumber[Range[12]]]/2 (* Paolo Xausa, Oct 20 2023 *)

Crossrefs

Cf. A000396, A139228, A139230, A139231, A139232, A139233, A139234, A139235, A139236, A139237.

Sequence in context: A033864 A142120 A252893 * A266652 A142672 A158297

Adjacent sequences: A139226 A139227 A139228 * A139230 A139231 A139232

Keyword

nonn

Author

Omar E. Pol, Apr 19 2008

Extensions

a(6)-a(9) from A139228(n)/2 by Jinyuan Wang, Mar 04 2020

Status

approved