A086356 Fixed point if [nonzero-digit product]-function at initial-value=C[2n,n]=central binomial coefficient is iterated.

2, 6, 2, 7, 2, 4, 4, 2, 2, 6, 6, 6, 8, 6, 5, 8, 8, 4, 8, 2, 9, 8, 6, 8, 6, 2, 8, 8, 2, 8, 6, 2, 6, 6, 8, 2, 6, 6, 6, 8, 9, 2, 2, 8, 2, 8, 2, 8, 6, 4, 2, 2, 8, 8, 2, 8, 6, 8, 2, 8, 6, 8, 9, 6, 6, 2, 6, 2, 2, 2, 8, 6, 8, 6, 8, 2, 8, 8, 8, 8, 8, 8, 6, 2, 6, 2, 8, 6, 8, 8, 8, 8, 8, 6, 8, 8, 6, 8, 2, 8, 2, 8, 6, 8, 8

Offset

1,1

Links

Table of n, a(n) for n=1..105.

Formula

a(n)=A051802[A000984(n)]=fixed-point of A051801[C(2n, n)]

Example

n=10, C[20,10]=184756, iteration list={184756,7560,210,2},
a(100)=2.

Mathematica

prd[x_] := Apply[Times, DeleteCases[IntegerDigits[x], 0]] Table[FixedPoint[prd, Binomial[2*n, n]], {w, 1, 128}]

Crossrefs

Cf. A051801, A051802, A086353-A086361, A029898, A010888, A038194, A000984.

Sequence in context: A078992 A062321 A229479 * A242435 A086359 A091944

Adjacent sequences: A086353 A086354 A086355 * A086357 A086358 A086359

Keyword

base,nonn

Author

Labos Elemer, Jul 21 2003

Status

approved