cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A202285 Numbers k such that the sum of digits^5 of k equals Sum_{d|k, 1 d.

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%I A202285 #15 Feb 14 2021 18:34:03
%S A202285 118678,459385,4150651,4351003,15033631,20402671,33224707,35188159,
%T A202285 40460929,42454261,50067673,54610051,62004127,77278261,88720939,
%U A202285 106412347,113660551,113852653,118203559,121732873,125252137,128083639,162748279,163869049,164863987
%N A202285 Numbers k such that the sum of digits^5 of k equals Sum_{d|k, 1<d<k} d.
%C A202285 The sequence is finite because the restricted sum of divisors of n, for n composite, is at least sqrt(n), while the sum of the fifth powers of the digits of n is at most 9^5*log_10(n+1). Last term is a(404) = 23184988999. - _Giovanni Resta_, Oct 05 2018
%H A202285 Giovanni Resta, <a href="/A202285/b202285.txt">Table of n, a(n) for n = 1..404</a> (full sequence)
%e A202285 k=118678 is in the sequence because 1^5 + 1^5 + 8^5 + 6^5 + 7^5 + 8^5 = 90121, and the sum of the divisors 1 < d < k =  sigma(k) - k - 1 = 90121.
%t A202285 Q[n_]:=Module[{a=Total[Rest[Most[Divisors[n]]]]}, a == Total[IntegerDigits[n]^5]]; Select[Range[2, 10^7], Q]
%Y A202285 Cf. A070308, A202279, A202147, A202240.
%K A202285 nonn,base,fini,full
%O A202285 1,1
%A A202285 _Michel Lagneau_, Dec 15 2011
%E A202285 a(11)-a(25) and keywords fini and full added by _Giovanni Resta_, Oct 05 2018