A015877 Numbers k such that sigma(k) = sigma(k+9).

14, 16, 46, 446, 1146, 26766, 35805, 143605, 179086, 185946, 437745, 1187725, 1194646, 1327086, 1746946, 2201806, 2893605, 3003385, 3574725, 3730125, 4053586, 4928385, 5715325, 6220305, 7507946, 9423645, 9897186

Offset

1,1

Links

Donovan Johnson, Table of n, a(n) for n = 1..200

Mathematica

Select[Range[10000000], DivisorSigma[1, #]==DivisorSigma[1, # + 9] &] (* Vincenzo Librandi, Mar 10 2014 *)
Position[Partition[DivisorSigma[1, Range[10^7]], 10, 1], _?(#[[1]] == #[[10]]&), {1}, Heads->False]//Flatten (* Harvey P. Dale, Aug 25 2016 *)

Prog

(PARI) is(n)=sigma(n)==sigma(n+9) \\ Charles R Greathouse IV, Mar 09 2014

Crossrefs

Cf. A002961, A007373, A015861, A015863, A015865, A015866, A015867, A015876, A015880, A015881, A015882, A015883, A181647.

Sequence in context: A305885 A224402 A067844 * A192290 A152010 A352381

Adjacent sequences: A015874 A015875 A015876 * A015878 A015879 A015880

Keyword

nonn

Author

Robert G. Wilson v

Status

approved