A267430 Squares whose digit sum is not a prime.

0, 1, 4, 9, 36, 64, 81, 100, 121, 144, 169, 196, 225, 324, 361, 400, 441, 484, 529, 576, 729, 900, 961, 1089, 1225, 1296, 1521, 1681, 1764, 1849, 2025, 2116, 2304, 2601, 2916, 3025, 3249, 3364, 3481, 3600, 3969, 4356, 4489, 4624, 4761, 5041, 5184, 5476, 5625

Offset: 1

Author

Vincenzo Librandi, Jan 15 2016

Keywords

• nonn
• base
• easy

Comments

Complement of A065408.

Includes A016766. - Robert Israel, Jan 15 2016

Links

• Robert Israel, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A000290, A016766, A065408, A104211.

Programs

Magma

[n^2: n in [0..80] | not IsPrime(&+Intseq(n^2))];

Maple

remove(t->isprime(convert(convert(t,base,10),`+`)), [seq(i^2,i=0..100)]); # Robert Israel, Jan 15 2016

Mathematica

Select[Range[0,100]^2, ! PrimeQ[Total[IntegerDigits[#]]] &]

PARI

is(n) = issquare(n) && !ispseudoprime(sumdigits(n)); \\ Altug Alkan, Jan 15 2016

Extensions

a(1)=0 prepended by Altug Alkan Jan 15 2016

Edited by Bruno Berselli, Jan 15 2016