A023148 Numbers k such that prime(k) == 6 (mod k).

1, 5, 79, 445, 16055, 27067045, 1208198549, 1208198609, 1208198615, 2636913002983, 885992692751479, 885992692751483, 885992692751833, 43525513764815035, 43525513764815057, 43525513764815173, 43525513764816367

Offset: 1

Author

David W. Wilson

Keywords

• nonn
• more

Comments

a(18) > 2.8*10^20. - Giovanni Resta, Feb 23 2020

Crossrefs

Cf. A092048, A023143, A023144, A023145, A023146, A023147, A023149, A023150, A023151, A023152.

Programs

Mathematica

NextPrim[n_] := Block[{k = n + 1}, While[ !PrimeQ[k], k++ ]; k]; p = 1; Do[ If[ Mod[p = NextPrim[p], n] == 6, Print[n]], {n, 1, 10^9}] (* Robert G. Wilson v, Feb 18 2004 *)

Sage

def A023148(max) :
    terms = []
    p = 2
    for n in range(1, max+1) :
        if (p - 6) % n == 0 : terms.append(n)
        p = next_prime(p)
    return terms
# Eric M. Schmidt, Feb 05 2013

Extensions

Extended by Robert G. Wilson v, Feb 18 2004

a(7)-a(9) from Robert G. Wilson v, Feb 22 2006

First two terms inserted by Eric M. Schmidt, Feb 05 2013

a(10)-a(17) from Giovanni Resta, Feb 23 2020