A358693 - OEIS

%I #63 Jan 12 2023 19:25:49

%S 12,24,36,48,81,150,225,375,441,735,882,1014,1452,1521,1815,2023,2028,

%T 2178,2312,2535,2601,3549,3610,4046,4332,4335,4624,4913,5054,5415,

%U 5491,5780,6069,6137,6358,6647,6936,7581,7942,8664,8959,9386,9522,9747,10092,11532,12321,12615,12696

%N Numbers k such that k / (sum of digits of k) is the square of a prime.

%C Terms k from A001102 such that k / (sum of digits of k) is the square of a prime.

%t Select[Range[13000], PrimeQ[Sqrt[#/Plus @@ IntegerDigits[#]]] &] (* _Amiram Eldar_, Jan 01 2023 *)

%o (PARI) isok(k) = my(r); issquare(k/sumdigits(k), &r) && (denominator(r)==1) && isprime(r); \\ _Michel Marcus_, Jan 01 2023

%Y Cf. A001102, A001248, A007953.

%K nonn,base

%O 1,1

%A _Andi Fugard_, Jan 01 2023

%E More terms from _Michel Marcus_, Jan 01 2023