A104247 Primes that are the sum of digits of the first k primes for some k.

2, 5, 17, 19, 23, 31, 41, 61, 71, 83, 181, 269, 389, 419, 449, 631, 683, 727, 743, 809, 929, 1039, 1061, 1069, 1091, 1277, 1381, 1481, 1567, 1613, 1747, 1873, 1951, 1993, 2039, 2129, 2281, 2297, 2339, 2381, 2549, 2579

Offset

1,1

Links

M. F. Hasler, Table of n, a(n) for n = 1..1000

Formula

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

Example

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.

Prog

(Python)
from sympy import isprime, nextprime
def sd(n): return sum(map(int, str(n)))
def aupto(limit):
    alst, k, p, s = [], 1, 2, 2
    while s <= limit:
        if isprime(s): alst.append(s)
        k += 1; p = nextprime(p); s += sd(p)
    return alst
print(aupto(2579)) # Michael S. Branicky, Jul 18 2021

Crossrefs

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

Cf. A051351, A075544.

Sequence in context: A025553 A343775 A075544 * A215425 A205511 A215276

Adjacent sequences: A104244 A104245 A104246 * A104248 A104249 A104250

Keyword

nonn,base

Author

Zak Seidov, Feb 26 2005

Status

approved