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A086354 Fixed point if (nonzero-digit product)-function at initial value 2^n is iterated. 2
2, 4, 8, 6, 6, 8, 6, 6, 1, 8, 8, 2, 6, 2, 2, 4, 8, 2, 1, 6, 2, 2, 6, 8, 2, 8, 2, 8, 2, 2, 8, 6, 6, 2, 2, 6, 2, 2, 6, 8, 8, 6, 3, 4, 2, 2, 6, 6, 2, 8, 6, 2, 2, 9, 8, 6, 6, 5, 8, 2, 8, 8, 2, 6, 2, 8, 8, 8, 5, 8, 8, 8, 2, 8, 6, 4, 8, 6, 2, 7, 1, 8, 8, 4, 2, 8, 8 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Nathaniel Johnston, Table of n, a(n) for n = 1..10000

FORMULA

a(n) = A051802(2^n) = fixed point of A051801(2^n).

EXAMPLE

n=20, 2^20=1048576, iteration list={1048576,6720,84,32,6}, so a(20)=6.

MAPLE

A051801 := proc(n) local d, j: d:=convert(n, base, 10): return mul(`if`(d[j]=0, 1, d[j]), j=1..nops(d)): end: A086354 := proc(n) local m: m:=2^n: while(length(m)>1)do m:=A051801(m): od: return m: end: seq(A086354(n), n=1..100); # Nathaniel Johnston, May 04 2011

MATHEMATICA

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

CROSSREFS

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

Sequence in context: A329455 A292808 A300813 * A014257 A247576 A246821

Adjacent sequences:  A086351 A086352 A086353 * A086355 A086356 A086357

KEYWORD

base,easy,nonn

AUTHOR

Labos Elemer, Jul 21 2003

STATUS

approved

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Last modified February 26 18:29 EST 2020. Contains 332293 sequences. (Running on oeis4.)