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 A161897 Prime numbers p for which k = (3^p - 3 * 3^((p + 1) / 2) - 6p + 6) / (3p^2 - 3p) is an integer 5
 11, 23, 47, 59, 83, 107, 167, 179, 227, 263, 347, 359, 383, 467, 479, 503, 563, 587, 719, 839, 863, 887, 983, 1019, 1187, 1283, 1307, 1319, 1367, 1439, 1487, 1523, 1619, 1823, 1907, 2027, 2039, 2063, 2099, 2207, 2447, 2459, 2579, 2819, 2879, 2903, 2963, 2999 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Superset of the inverse Sophie Germain primes (A005385): (p - 1) / 2 is almost always prime. LINKS Robert Israel, Table of n, a(n) for n = 1..10000 MAPLE filter:= p -> isprime(p) and    (3&^p - 3 * 3&^((p + 1) / 2) - 6*p + 6) mod (3*p^2-3*p) = 0: select(filter, [seq(i, i=3..10000, 2)]); # Robert Israel, Mar 31 2017 CROSSREFS Cf. A161896, A000040, A005385, A158034, A158035, A158036, A145918. Sequence in context: A068231 A185005 A073024 * A282531 A309851 A145994 Adjacent sequences:  A161894 A161895 A161896 * A161898 A161899 A161900 KEYWORD easy,nonn AUTHOR Reikku Kulon, Jun 21 2009 STATUS approved

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Last modified June 15 12:29 EDT 2021. Contains 345048 sequences. (Running on oeis4.)