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A133500 Powertrain(n): if abcd... is the decimal expression of a number n, then the powertrain of n is the number n' = a^b*c^d* ..., which ends in an exponent or a base according as the number of digits is even or odd. a(0) = 0 by convention. +0
16
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1, 3, 9, 27, 81, 243, 729, 2187, 6561, 19683, 1, 4, 16, 64, 256, 1024, 4096, 16384, 65536, 262144, 1, 5, 25, 125, 625, 3125, 15625, 78125, 390625, 1953125, 1, 6, 36, 216, 1296 (list; graph; listen)
OFFSET

0,3

COMMENT

We take 0^0 = 1.

The fixed points are in A135385.

LINKS

N. J. A. Sloane, Table of n, a(n) for n = 0..10000

MAPLE

powertrain:=proc(n) local a, i, n1, n2, t1, t2; n1:=abs(n); n2:=sign(n); t1:=convert(n1, base, 10); t2:=nops(t1); a:=1; for i from 0 to floor(t2/2)-1 do a := a*t1[t2-2*i]^t1[t2-2*i-1]; od: if t2 mod 2 = 1 then a:=a*t1[1]; fi; RETURN(n2*a); end; - njas, Dec 03 2007

CROSSREFS

Cf. A133501-A133502, A135385. For records see A133504, A133505.

Cf. A133048 (powerback), A031346 and A003001 (persistence).

Sequence in context: A055017 A040997 A075877 this_sequence A052423 A126616 A121042

Adjacent sequences: A133497 A133498 A133499 this_sequence A133501 A133502 A133503

KEYWORD

nonn,base

AUTHOR

John Conway, Dec 03 2007

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Last modified August 19 23:53 EDT 2008. Contains 142930 sequences.


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