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

Author

Jaroslav Krizek, May 09 2010

Keywords

• nonn
• base

Examples

			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.
		

Crossrefs

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

Programs

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 *)