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A175420 Sequence of resulting numbers after 1st step of iteration defined in A175419. 9
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 4, 9, 16, 25, 36, 49, 64, 81, 0, 1, 8, 27, 64, 125, 216, 343, 512, 729, 0, 1, 16, 81, 256, 625, 1296, 2401, 4096, 6561, 0, 1, 32, 243, 1024, 3125, 7776, 16807, 32768, 59049, 0, 1, 64, 729, 4096, 15625, 46656 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Table of n, a(n) for n=0..66.

FORMULA

a(n) = (((D_k^D_(k-1))^D_(k-2))^...)^D_1, where D_k = k-th digit D of number n and k = the number of digits of number n in decimal expansion of n (A055642).

EXAMPLE

For n = 33: a(33) = 27 because for the number 33 there are 4 steps of defined iteration: {3^3 = 27}, {7^2 = 49}, {9^4 = 6561}, {((1^6)^5)^6 = 1} and the 1st step of the iteration ends with 27.

MAPLE

A175420 := proc(n) local dgs, a, i ; if n = 0 then return 0 ; end if; dgs := convert(n, base, 10) ; a := op(1, dgs) ; for i from 2 to nops(dgs) do a := a^ op(i, dgs) ; end do: a ; end proc: seq(A175420(n), n=0..120) ; # R. J. Mathar, May 12 2010

PROG

(PARI) a(n) = if (n, my(d=digits(n), r=d[#d]); forstep (k=#d-1, 1, -1, r = r^d[k]; ); r); \\ Michel Marcus, Jan 20 2022

CROSSREFS

Cf. A175419, A175421, A175422, A175423, A175424, A175425, A175426, A175427.

Cf. A055642.

Sequence in context: A175422 A175423 A175421 * A062078 A031347 A087471

Adjacent sequences: A175417 A175418 A175419 * A175421 A175422 A175423

KEYWORD

nonn,base

AUTHOR

Jaroslav Krizek, May 09 2010

EXTENSIONS

More terms from R. J. Mathar, May 12 2010

STATUS

approved

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Last modified December 5 01:43 EST 2022. Contains 358572 sequences. (Running on oeis4.)