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.
%I A290944 #20 Sep 08 2022 08:46:19 %S A290944 3,1753,1999,2389,2713,3301,3361,3529,3583,3607,3631,3643,3697,3889, %T A290944 3907,4093,4099,4129,4153,4159,4243,4423,4591,4639,4813,5167,5449, %U A290944 5503,5527,5563,5683,5689,5827,6199,6211,6427,6529,6553,6691,6709,6883,6949,6961,6997 %N A290944 Primes p such that sum of digits of p^3 is a perfect square. %C A290944 All the terms in this sequence, except a(1), are congruent to 1 mod 3. %C A290944 After a(1), all the terms are congruent to {1, 4, 7} mod 9. %H A290944 K. D. Bajpai, <a href="/A290944/b290944.txt">Table of n, a(n) for n = 1..10000</a> %e A290944 a(1) = 3 is prime: 3^3 = 27; 2 + 7 = 9 = 3^2. %e A290944 a(2) = 1753 is prime: 1753^3 = 5386984777; 5 + 3 + 8 + 6 + 9 + 8 + 4 + 7 + 7 + 7 = 64 = 8^2. %p A290944 f:= n->add(d, d=convert(n^3, base, 10)): %p A290944 select(t -> type(sqrt(f(t)), integer), [seq(ithprime(m), m=1..10^3)]); %t A290944 Select[Prime[Range[2000]], IntegerQ[Sqrt[Plus @@ IntegerDigits[#^3]]] &] %o A290944 (PARI) forprime(p=1, 5000, if(issquare(sumdigits(p^3)), print1(p, ", "))); %o A290944 (Magma) [p: p in PrimesUpTo(1000) | IsSquare(&+Intseq(p^3))]; %o A290944 (PARI) is(n) = ispseudoprime(n) && issquare(sumdigits(n^3)) \\ _Felix Fröhlich_, Aug 14 2017 %Y A290944 Cf. A007605, A052279, A079130, A086924, A235398, A259418, A290843. %K A290944 nonn,base %O A290944 1,1 %A A290944 _K. D. Bajpai_, Aug 14 2017