A104247 - OEIS

%I #17 Feb 24 2024 01:10:29

%S 2,5,17,19,23,31,41,61,71,83,181,269,389,419,449,631,683,727,743,809,

%T 929,1039,1061,1069,1091,1277,1381,1481,1567,1613,1747,1873,1951,1993,

%U 2039,2129,2281,2297,2339,2381,2549,2579

%N Primes that are the sum of digits of the first k primes for some k.

%H M. F. Hasler, <a href="/A104247/b104247.txt">Table of n, a(n) for n = 1..1000</a>

%F a(n) = A007605(1) + ... + A007605(A058049(n)).

%e a(4)=19 because A058049(4)= 5 and sum of digits of the first 5 primes, 2+3+5+7+(1+1)=19 is prime.

%o (Python)

%o from sympy import isprime, nextprime

%o def sd(n): return sum(map(int, str(n)))

%o def aupto(limit):

%o     alst, k, p, s = [], 1, 2, 2

%o     while s <= limit:

%o         if isprime(s): alst.append(s)

%o         k += 1; p = nextprime(p); s += sd(p)

%o     return alst

%o print(aupto(2579)) # _Michael S. Branicky_, Jul 18 2021

%Y Corresponding n's: A058049. Primes: A000040, sum of digits of primes: A007605.

%Y Cf. A051351, A075544.

%K nonn,base

%O 1,1

%A _Zak Seidov_, Feb 26 2005