A065408 Squares whose digits sum to a prime.

16, 25, 49, 256, 289, 625, 676, 784, 841, 1024, 1156, 1369, 1444, 1600, 1936, 2209, 2401, 2500, 2704, 2809, 3136, 3721, 3844, 4096, 4225, 4900, 5329, 6241, 6724, 6889, 7921, 8281, 9604, 11236, 11449, 11881, 13225, 13456, 13924, 14161, 15625, 16129

Offset: 1

Author

Jason Earls, Nov 22 2001

Keywords

• base
• easy
• nonn

Links

• Harry J. Smith, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A000290, A007953, A107289.

Programs

Mathematica

Select[Range[1000]^2,PrimeQ[Total[IntegerDigits[#]]]&]

PARI

{ for (m=1, 200, if (isprime(sumdigits(m^2)), print1(m^2, ", "))) } \\ Harry J. Smith, Oct 18 2009

Formula

a(n) = A107289(n)^2. - Andrew Howroyd, Dec 05 2024