cp's OEIS Frontend

A175405 Numbers m such that the resulting number h after iterations of {((((D_1^D_2)^D_3)^D_4)^...)^D_k, where D_k is the k-th digit D of the number r and k is the digit number of the number r in the decimal expansion of r (A055642)} needed to reach a one-digit number starting at r = n is equal to 1 (h = 1).

%I A175405 #11 Oct 13 2024 00:17:48
%S A175405 1,10,11,12,13,14,15,16,17,18,19,20,24,26,27,28,30,33,35,36,37,38,39,
%T A175405 40,42,43,44,45,46,47,48,49,50
%N A175405 Numbers m such that the resulting number h after iterations of {((((D_1^D_2)^D_3)^D_4)^...)^D_k, where D_k is the k-th digit D of the number r and k is the digit number of the number r in the decimal expansion of r (A055642)} needed to reach a one-digit number starting at r = n is equal to 1 (h = 1).
%e A175405 For number a(14) = 26 we have iteration: {2^6 = 64}, {6^4 = 1296}, {((1^2)^9)^6 = 1}.
%Y A175405 Cf. A175398, A175399, A175400, A175401, A175402, A175403.
%K A175405 nonn,base,more
%O A175405 1,2
%A A175405 _Jaroslav Krizek_, May 01 2010