A076161 Numbers n such that n + sum of squares of digits of n (A258881) is a prime.

1, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 31, 34, 57, 73, 74, 75, 78, 91, 94, 97, 100, 101, 102, 103, 105, 107, 108, 109, 121, 122, 123, 126, 127, 128, 140, 142, 146, 148, 160, 161, 165, 166, 168, 182, 183, 188, 213, 216, 217, 234, 251, 275, 277, 297, 301

Offset: 1

Author

Zak Seidov, Nov 01 2002

Keywords

• nonn
• base

Examples

			12 is a term because 12+(1^2+2^2) = 17 is a prime.
		

Links

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

Crossrefs

Cf. A258881, A259391, A259567.

Programs

Maple

filter:= proc(n) local t; isprime(n+add(t^2,t=convert(n,base,10))) end proc:
select(filter, [$1..1000]); # Robert Israel, Jan 30 2021

PARI

isok(n) = isprime(n + norml2(digits(n))); \\ Michel Marcus, Jan 31 2021

Python

from sympy import isprime
def ssd(n): return sum(int(d)**2 for d in str(n))
def ok(n): return isprime(n + ssd(n))
def aupto(limit): return [m for m in range(1, limit+1) if ok(m)]
print(aupto(301)) # Michael S. Branicky, Jan 30 2021