login
A066894
Numbers k such that prime(2*k) - prime(k) == 0 (mod k).
0
1, 2, 4, 6, 18, 42, 44, 49, 246, 257, 259, 272, 283, 294, 25284, 62648, 62664, 62673, 62700, 62701, 158706, 404835, 404859, 405119, 405448, 405451, 2630908, 2630929, 2631249, 2631303, 2631368, 2631414, 2631509, 2631517, 2631576, 2631666, 17405852, 44932936
OFFSET
1,2
EXAMPLE
prime(2*2) - prime(2) = 7 - 3 = 4 that is equal to 0 mod 2, so 2 is in the sequence.
PROG
(PARI) isok(n) = (prime(2*n)-prime(n)) % n == 0; \\ Michel Marcus, Nov 20 2013
CROSSREFS
Cf. A072473.
Sequence in context: A098853 A023149 A085146 * A233919 A111115 A195328
KEYWORD
nonn
AUTHOR
Benoit Cloitre, Jan 24 2002
EXTENSIONS
a(15)-a(20) from Michel Marcus, Nov 20 2013
a(21)-a(38) from Donovan Johnson, Nov 20 2013
STATUS
approved