A063112 a(1) = 1; a(n+1) = a(n) + product of nonzero digits of a(n) when written in base 3. Display sequence in base 3.

1, 2, 11, 12, 21, 100, 101, 102, 111, 112, 121, 200, 202, 220, 1001, 1002, 1011, 1012, 1021, 1100, 1101, 1102, 1111, 1112, 1121, 1200, 1202, 1220, 2001, 2010, 2012, 2100, 2102, 2120, 2201, 2212, 10011, 10012, 10021, 10100, 10101, 10102, 10111, 10112

Offset: 1

Author

N. J. A. Sloane, Aug 08 2001

Keywords

• nonn
• base

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

Crossrefs

Cf. A063108, A063113, A063114.

Programs

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("b063112.txt", n, " ", a) ) } \\ Harry J. Smith, Aug 19 2009

Extensions

More terms from Vladeta Jovovic, Aug 10 2001