cp's OEIS Frontend

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

%I A076161 #21 Feb 01 2021 18:14:29
%S A076161 1,10,11,12,13,14,15,16,17,18,19,31,34,57,73,74,75,78,91,94,97,100,
%T A076161 101,102,103,105,107,108,109,121,122,123,126,127,128,140,142,146,148,
%U A076161 160,161,165,166,168,182,183,188,213,216,217,234,251,275,277,297,301
%N A076161 Numbers n such that n + sum of squares of digits of n (A258881) is a prime.
%H A076161 Robert Israel, <a href="/A076161/b076161.txt">Table of n, a(n) for n = 1..10000</a>
%e A076161 12 is a term because 12+(1^2+2^2) = 17 is a prime.
%p A076161 filter:= proc(n) local t; isprime(n+add(t^2,t=convert(n,base,10))) end proc:
%p A076161 select(filter, [$1..1000]); # _Robert Israel_, Jan 30 2021
%o A076161 (Python)
%o A076161 from sympy import isprime
%o A076161 def ssd(n): return sum(int(d)**2 for d in str(n))
%o A076161 def ok(n): return isprime(n + ssd(n))
%o A076161 def aupto(limit): return [m for m in range(1, limit+1) if ok(m)]
%o A076161 print(aupto(301)) # _Michael S. Branicky_, Jan 30 2021
%o A076161 (PARI) isok(n) = isprime(n + norml2(digits(n))); \\ _Michel Marcus_, Jan 31 2021
%Y A076161 Cf. A258881, A259391, A259567.
%K A076161 nonn,base
%O A076161 1,2
%A A076161 _Zak Seidov_, Nov 01 2002