A058846 Numbers k such that the sum of odd primes up to k is palindromic.

3, 5, 229, 257, 1031, 7213, 11863, 133853, 1002073, 31924583, 97137589, 1837875227

Offset

1,1

Comments

Sum is 3 + 5 + 7 + 11 + 13 + 17 + ... + k.

a(13) > 8.79*10^13, if it exists. - Giovanni Resta, Sep 01 2018

Links

Table of n, a(n) for n=1..12.

Patrick De Geest, Palindromic Sums

Formula

a(n) = A065091(A058845(n)). - R. J. Mathar, Sep 09 2015

Prog

(PARI) lista(nn) = {s = 0; p = 2; for (n=1, nn, p = nextprime(p+1); s += p; d = digits(s); if (Vecrev(d) == d, print1(p, ", ")); ); } \\ Michel Marcus, Aug 09 2017
(Python)
from sympy import primerange
def ispal(n): s = str(n); return s == s[::-1]
def afind(limit):
  s = 0
  for p in primerange(3, limit):
    s += p
    if ispal(s): print(p, end=", ")
afind(2*10**6) # Michael S. Branicky, Mar 05 2021

Crossrefs

Cf. A065091, A058845, A058847, A071148, A038584.

Sequence in context: A175133 A012817 A087367 * A268535 A268695 A167483

Adjacent sequences: A058843 A058844 A058845 * A058847 A058848 A058849

Keyword

nonn,base,more

Author

Patrick De Geest, Dec 15 2000

Status

approved