A076503 Prime numbers whose squares have square digit-sums.

2, 3, 11, 13, 23, 31, 41, 59, 67, 101, 103, 113, 131, 139, 157, 193, 211, 229, 239, 257, 283, 311, 337, 347, 373, 401, 409, 419, 463, 491, 499, 509, 571, 599, 643, 653, 661, 743, 751, 761, 769, 797, 1013, 1021, 1031, 1039, 1103, 1129, 1193, 1201, 1229, 1237

Offset: 1

Author

Christopher Schloetz (cschloetz(AT)hotmail.com), Nov 09 2002

Keywords

• nonn
• base

Examples

			13 is a member because 13 is prime and the digit-sum of its square is 1+6+9=16, which is also square.
		

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A000040, A061910.

Programs

Mathematica

Select[Prime[Range[250]],IntegerQ[Sqrt[Total[IntegerDigits[#^2]]]]&] (* Harvey P. Dale, Aug 30 2016 *)

PARI

isok(n) = if (! isprime(n), 0, d = digits(n^2); issquare(sum(i=1, #d, d[i]))) \\ Michel Marcus, Jun 20 2013

Extensions

More terms from Michel ten Voorde Jun 13 2003