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A067185
Numbers k such that prime(k+1) + prime(k) == 1 (mod k).
3
1, 7, 17, 109, 281, 1669, 6592663, 16899113, 16899145, 16899295, 749973611, 5067034877, 5067034925, 34487825911, 1626582230375
OFFSET
1,2
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
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