A190654 Twin Ramanujan primes.

149, 151, 179, 181, 227, 229, 239, 241, 347, 349, 431, 433, 569, 571, 599, 601, 641, 643, 821, 823, 1019, 1021, 1049, 1051, 1061, 1063, 1427, 1429, 1487, 1489, 1607, 1609, 1787, 1789, 1997, 1999, 2081, 2083, 2129, 2131, 2237, 2239, 2267, 2269, 2657, 2659, 2687, 2689, 2711, 2713, 2789, 2791, 2999, 3001, 3167, 3169, 3257, 3259, 3299, 3301, 3359, 3361, 3527, 3529, 3539, 3541

Offset: 1

Author

Jonathan Sondow, May 16 2011

Keywords

• nonn

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A178127 (lesser of twin Ramanujan primes).

Programs

Mathematica

FasterRamanujanPrimeList[n_] := With[{T = Table[{k, PrimePi[k] - PrimePi[k/2]}, {k, Prime[3*n]}]}, Table[1 + First[Last[Select[T, Last[#] == i - 1 &]]], {i, 1, n}]]; Select[Partition[FasterRamanujanPrimeList[222], 2, 1], First[#] == Last[#] - 2 &]//Flatten (* Robert P. P. McKone, Mar 21 2022 *)

Formula

a(2n-1) = A178127(n).

a(2n) = A178127(n) + 2.