A167277 Largest nonprime<n-th single (or isolated or non-twin) prime.

1, 22, 36, 46, 52, 66, 78, 82, 88, 96, 112, 126, 130, 156, 162, 166, 172, 210, 222, 232, 250, 256, 262, 276, 292, 306, 316, 330, 336, 352, 358, 366, 372, 378, 382, 388, 396, 400, 408, 438, 442, 448, 456, 466, 478, 486, 490, 498, 502, 508, 540, 546, 556, 562

Offset

1,2

Comments

Or, n-th single prime minus smallest divisor of n-th single prime.

Links

Harvey P. Dale, Table of n, a(n) for n = 1..2500

Formula

a(n) = A007510(n) - 1

Mathematica

Select[Prime[Range[150]], NoneTrue[#+{2, -2}, PrimeQ]&]-1 (* Harvey P. Dale, Dec 26 2022 *)

Crossrefs

Sequence in context: A100039 A061561 A233404 * A084141 A259736 A082261

Adjacent sequences: A167274 A167275 A167276 * A167278 A167279 A167280

Keyword

nonn

Author

Juri-Stepan Gerasimov, Nov 01 2009

Extensions

Entries checked by R. J. Mathar, May 21 2010

Status

approved