A067185 Numbers k such that prime(k+1) + prime(k) == 1 (mod k).

1, 7, 17, 109, 281, 1669, 6592663, 16899113, 16899145, 16899295, 749973611, 5067034877, 5067034925, 34487825911, 1626582230375

Offset

1,2

Links

Table of n, a(n) for n=1..15.

Mathematica

a = b = 0; Do[b = Prime[n + 1]; If[Mod[a + b, n] == 1, Print[n]]; a = b, {n, 1, 10^9}]

Prog

(Sage)
def A067185(max):
    terms = []
    p = 2
    for n in range(1, max + 1):
        q = next_prime(p)
        if not (p + q - 1) % n:
            terms.append(n)
        p = q
    return terms
# Eric M. Schmidt, Feb 05 2013
(PARI) isok(k) = (prime(k+1) + prime(k)) % k == 1; \\ Michel Marcus, Feb 17 2021

Crossrefs

Cf. A066895 (== 0 instead of 1).

Sequence in context: A181605 A284209 A068172 * A205989 A262474 A284416

Adjacent sequences: A067182 A067183 A067184 * A067186 A067187 A067188

Keyword

nonn,more

Author

Benoit Cloitre, Feb 19 2002

Extensions

Edited and extended by Robert G. Wilson v, Feb 19 2002

Extended by David W. Wilson, Feb 20 2002

a(11)-a(14) from Donovan Johnson, Mar 10 2010

First term from Eric M. Schmidt, Feb 05 2013

Status

approved