A065408 -id:A065408 - cp's OEIS frontend

A107289 Numbers k such that the sum of digits of k^2 is a prime.

4, 5, 7, 16, 17, 25, 26, 28, 29, 32, 34, 37, 38, 40, 44, 47, 49, 50, 52, 53, 56, 61, 62, 64, 65, 70, 73, 79, 82, 83, 89, 91, 98, 106, 107, 109, 115, 116, 118, 119, 125, 127, 133, 137, 142, 143, 146, 149, 151, 154, 155, 160, 161, 164, 170, 173, 181, 182, 187, 188, 199

Offset: 1

Zak Seidov, May 20 2005

Cf. A065408.

bb={};Do[If[PrimeQ[Apply[Plus, IntegerDigits[n^2]]], bb=Append[bb, n]], {n, 500}];bb

isok(n) = isprime(sumdigits(n^2)); \\ Michel Marcus, Jan 09 2019

a(n) = sqrt(A065408(n)).

A267430 Squares whose digit sum is not a prime.

Original entry on oeis.org

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

Vincenzo Librandi, Jan 15 2016

Complement of A065408.

Includes A016766. - Robert Israel, Jan 15 2016

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

Cf. A000290, A016766, A065408, A104211.

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

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

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

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

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

Edited by Bruno Berselli, Jan 15 2016

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A107289 Numbers k such that the sum of digits of k^2 is a prime.

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A267430 Squares whose digit sum is not a prime.

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