A070280 a(1) = 1; a(n) = a(n-1) + product of the digits of n-1.

1, 2, 4, 7, 11, 16, 22, 29, 37, 46, 46, 47, 49, 52, 56, 61, 67, 74, 82, 91, 91, 93, 97, 103, 111, 121, 133, 147, 163, 181, 181, 184, 190, 199, 211, 226, 244, 265, 289, 316, 316, 320, 328, 340, 356, 376, 400, 428, 460, 496, 496, 501, 511, 526, 546, 571, 601, 636, 676, 721, 721, 727, 739, 757, 781, 811, 847, 889, 937, 991, 991

Offset

1,2

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Example

a(12) = a(11) + product of digits of 11 = 46 + 1 = 47.

Mathematica

a[n_] := a[n] = (a[n - 1] + Times @@ IntegerDigits[n - 1]); a[1] = 1; Table[ a[n], {n, 1, 60}]
nxt[{n_, a_}]:={n+1, a +Times@@IntegerDigits[n]}; NestList[nxt, {1, 1}, 70][[All, 2]] (* Harvey P. Dale, Jan 23 2021 *)

Crossrefs

Sequence in context: A348575 A348400 A025726 * A025707 A337919 A025733

Adjacent sequences: A070277 A070278 A070279 * A070281 A070282 A070283

Keyword

base,nonn

Author

Joseph L. Pe, May 09 2002

Extensions

Edited by Robert G. Wilson v, May 14 2002

Corrected and extended by Harvey P. Dale, Jan 23 2021

Status

approved