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A329386 Numbers k such that k + A055012(k) is a square.

%I A329386 #18 Sep 08 2022 08:46:24
%S A329386 17,104,216,260,342,392,500,518,540,590,746,830,848,1008,1073,1077,
%T A329386 1166,1169,1233,1313,1694,1784,1835,1962,1998,2252,2420,2897,3006,
%U A329386 3047,3087,3302,3762,4316,4416,4424,4706,4928,5031,5126,5273,5435,6137,6399,6813,7134,7259,7442,7449,7655,7895,7992
%N A329386 Numbers k such that k + A055012(k) is a square.
%H A329386 Robert Israel, <a href="/A329386/b329386.txt">Table of n, a(n) for n = 1..10000</a>
%e A329386 a(3)=216 is a term because 216 + 2^3 + 1^3 + 6^3 = 441 = 21^2.
%p A329386 filter:= proc(n) local t;
%p A329386   issqr( n + add(t^3,t=convert(n,base,10)));
%p A329386 end proc:
%p A329386 select(filter, [$1..10000]);
%o A329386 (Magma) [k:k in [1..8000]|IsSquare(k+&+[c^3: c in Intseq(k)])]; // _Marius A. Burtea_, Nov 12 2019
%o A329386 (PARI) A055012(n)=sum(i=1, #n=digits(n), n[i]^3)
%o A329386 is(n)=issquare(n + A055012(n)) \\ _Charles R Greathouse IV_, Jun 10 2020
%Y A329386 Cf. A055012, A329179.
%K A329386 nonn,base
%O A329386 1,1
%A A329386 _Will Gosnell_ and _Robert Israel_, Nov 12 2019