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Product of nonzero digits(sum of digits(n^n)).
1

%I #10 Dec 31 2023 16:34:43

%S 1,4,9,3,1,14,10,21,20,1,4,20,40,10,81,64,72,8,14,3,7,32,24,15,5,20,

%T 72,18,42,18,32,10,14,8,12,14,14,60,18,2,24,15,9,30,18,30,84,27,75,5,

%U 16,8,15,168,32,27,20,56,28,24,128,20,180,224,70,15,60,120,196,90,144,200,24

%N Product of nonzero digits(sum of digits(n^n)).

%C Conjecture: a(n) = a(n+1) for infinitely many positive integers. Largest found is n=4462, i.e. pnd(sd(4462^4462)) = pnd(sd(4463^4463)) = 126.

%H Harvey P. Dale, <a href="/A096301/b096301.txt">Table of n, a(n) for n = 1..1000</a>

%t Array[Times@@Select[IntegerDigits[Total[IntegerDigits[#^#]]],#>0&]&,80] (* _Harvey P. Dale_, Sep 30 2012 *)

%Y Cf. A051801, A007953.

%K base,easy,nonn

%O 1,2

%A _Jason Earls_, Jun 25 2004