A063113 a(1) = 1; a(n+1) = a(n) + product of nonzero digits of a(n) when written in base 3. But display sequence in base 10.

1, 2, 4, 5, 7, 9, 10, 11, 13, 14, 16, 18, 20, 24, 28, 29, 31, 32, 34, 36, 37, 38, 40, 41, 43, 45, 47, 51, 55, 57, 59, 63, 65, 69, 73, 77, 85, 86, 88, 90, 91, 92, 94, 95, 97, 99, 101, 105, 109, 110, 112, 113, 115, 117, 118, 119, 121, 122, 124, 126, 128, 132, 136, 138

Offset

1,2

Links

Harry J. Smith, Table of n, a(n) for n = 1..1000

P. A. Loomis, An Interesting Family of Iterated Sequences

P. A. Loomis, An Introduction to Digit Product Sequences, J. Rec. Math., 32 (2003-2004), 147-151.

P. A. Loomis, An Introduction to Digit Product Sequences, J. Rec. Math., 32 (2003-2004), 147-151. [Annotated archived copy]

Index entries for Colombian or self numbers and related sequences

Mathematica

f[n_Integer] := (a = Sort[ IntegerDigits[n, 3]]; While[ a[[1]] == 0, a = Delete[a, 1]]; n + Apply[ Times, a] ); NestList[f, 1, 65]

Prog

(PARI) baseE(x, b)= { local(d, e, f); e=0; f=1; while (x>0, d=x-b*(x\b); x\=b; e+=d*f; f*=10); return(e) }
ProdNzD(x)= { local(d, p); p=1; while (x>9, d=x-10*(x\10); if (d, p*=d); x\=10); return(p*x) }
{ for (n=1, 1000, if (n>1, a=baseE(b+= ProdNzD(a), 3), a=1; b=1); write("b063113.txt", n, " ", b) ) } \\ Harry J. Smith, Aug 19 2009

Crossrefs

Cf. A063108, A063112, A063114.

Sequence in context: A185598 A185550 A189629 * A122825 A159615 A026463

Adjacent sequences: A063110 A063111 A063112 * A063114 A063115 A063116

Keyword

nonn,base

Author

N. J. A. Sloane, Aug 08 2001

Extensions

More terms from Robert G. Wilson v, Aug 09 2001

Status

approved