A103968 Sigma((8^n - 1)/7), where sigma(n) is the sum of positive divisors of n.

1, 13, 74, 1092, 4864, 59200, 346112, 4756752, 19436692, 251916288, 1294876800, 20786304000, 79541043200, 1073030266880, 5303003316224, 81061789640832, 324992122224640, 4102172934143680, 20588576135708672, 376372958524932096

Offset

1,2

Links

Amiram Eldar, Table of n, a(n) for n = 1..402

Formula

a(n) = A000203(A023001(n)). - Amiram Eldar, Feb 24 2020

Mathematica

DivisorSigma[1, (8^Range[20]-1)/7] (* Harvey P. Dale, Aug 21 2011 *)

Crossrefs

Cf. A000203, A023001.

Sequence in context: A094421 A301882 A302079 * A073544 A051361 A114070

Adjacent sequences: A103965 A103966 A103967 * A103969 A103970 A103971

Keyword

nonn

Author

Jun Mizuki (suzuki32(AT)sanken.osaka-u.ac.jp), Mar 31 2005

Status

approved