A175421 Sequence of numbers after 2nd step of iteration defined in A175419.

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 4, 9, 6, 25, 216, 6561, 4096, 1, 0, 1, 8, 49, 4096, 25, 36, 531441, 32, 22876792454961, 0, 1, 6, 1, 60466176, 244140625, 101559956668416, 1, 1, 1, 0

Offset

0,3

Links

Table of n, a(n) for n=0..50.

Example

For n = 33: a(33) = 49 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 2nd step of the iteration ends with 49.

Mathematica

Unprotect[Power]; Power[0, 0] = 1; Protect[Power]; A175420[0]=0; A175420[n_]:=If[(len=IntegerLength[n])==1, n, Last[list=IntegerDigits[n]]^Product[Part[Drop[list, -1], i], {i, len-1}]]; a[n_]:=A175420[A175420[n]]; Array[a, 51, 0] (* Stefano Spezia, Feb 25 2024 *)

Crossrefs

Cf. A175419, A175420, A175422, A175423, A175424, A175425, A175426, A175427.

Sequence in context: A175419 A175422 A175423 * A175420 A062078 A371281

Adjacent sequences: A175418 A175419 A175420 * A175422 A175423 A175424

Keyword

nonn,base

Author

Jaroslav Krizek, May 09 2010

Status

approved