A226361 Numbers n such that sigma(n) = sigma(n+1) + sigma(n+2).

378624, 661152, 5479092, 5526024, 7179624, 18744216, 122321970, 168201288, 215676636, 778701984, 1482154170, 1788138780, 1974360132, 2288979096, 3361923780, 4214315484, 4757106144, 4971510492, 6264306144, 6884356716, 10730488296, 11375549304, 16851779736

Offset

1,1

Links

Giovanni Resta, Table of n, a(n) for n = 1..88 (terms < 10^13)

Mathematica

nn = 10^7; t = {}; sig0 = 1; sig1 = 3; Do[sig2 = DivisorSigma[1, n + 2]; If[sig0 == sig1 + sig2, AppendTo[t, n]]; sig0 = sig1; sig1 = sig2, {n, nn}]; t (* T. D. Noe, Jun 05 2013 *)

Crossrefs

Cf. A000203, A055574, A065900, A073500, A099632.

Sequence in context: A203740 A283030 A318964 * A238078 A133975 A133977

Adjacent sequences: A226358 A226359 A226360 * A226362 A226363 A226364

Keyword

nonn

Author

Alex Ratushnyak, Jun 05 2013

Extensions

a(17)-a(23) from Donovan Johnson, Jun 05 2013

Status

approved