A095992 a(1) = 30; for n > 1, a(n+1) = a(n) + {product of nonzero digits of a(n)}.

30, 33, 42, 50, 55, 80, 88, 152, 162, 174, 202, 206, 218, 234, 258, 338, 410, 414, 430, 442, 474, 586, 826, 922, 958, 1318, 1342, 1366, 1474, 1586, 1826, 1922, 1958, 2318, 2366, 2582, 2742, 2854, 3174, 3258, 3498, 4362, 4506, 4626, 4914, 5058, 5258, 5658

Offset: 1

Author

Julien Piquet (julipiquet(AT)yahoo.fr), Jul 18 2004

Keywords

• nonn
• base
• easy

References

• From a puzzle; explanation found by Pierre Roger.

Links

• Frank Rubin, Number Series

Crossrefs

Cf. A063108, A096347, A096972, A063108, A063425, A096922, A096923, A096924, A096925, A096926, A096927, A096928, A096929, A096930, A096931, A096973, A096987.

Programs

Mathematica

a[1] = 30; a[n_] := a[n] = Block[{s = Sort[ IntegerDigits[a[n - 1]]]}, While[ s[[1]] == 0, s = Drop[s, 1]]; a[n - 1] + Times @@ s]; Table[ a[n], {n, 50}]
nxt[n_] := n+Times@@Select[IntegerDigits[n], #>0&]; NestList[nxt,30,50] (* Harvey P. Dale, Jan 08 2011 *)

Extensions

The proposer suggests that this web site may contain other sequences also.

Edited and extended by Robert G. Wilson v and Klaus Brockhaus, Jul 20 2004