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

1,1

Links

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

Formula

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

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

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 *)

Crossrefs

Cf. A178127 (lesser of twin Ramanujan primes).

Sequence in context: A248412 A182874 A268428 * A308895 A100723 A316589

Adjacent sequences: A190651 A190652 A190653 * A190655 A190656 A190657

Keyword

nonn

Author

Jonathan Sondow, May 16 2011

Status

approved