A163656 Arithmetic mean of the n-th and (n+1)st twin prime member A001097.

4, 6, 9, 12, 15, 18, 24, 30, 36, 42, 51, 60, 66, 72, 87, 102, 105, 108, 123, 138, 144, 150, 165, 180, 186, 192, 195, 198, 213, 228, 234, 240, 255, 270, 276, 282, 297, 312, 330, 348, 384, 420, 426, 432, 447, 462, 492, 522, 546, 570, 585, 600, 609, 618, 630, 642

Offset

1,1

Links

T. D. Noe, Table of n, a(n) for n = 1..10000

Formula

a(n) = (A001097(n) + A001097(n+1))/2.

Example

a(1) = 4 = (3+5)/2.

Mathematica

t = Select[Prime[Range[500]], PrimeQ[# - 2] || PrimeQ[# + 2] &]; (Most[t] + Rest[t])/2 (* T. D. Noe, Aug 07 2012 *)

Crossrefs

Cf. A014574 (bisection).

Sequence in context: A162735 A024675 A274135 * A134678 A100915 A144922

Adjacent sequences: A163653 A163654 A163655 * A163657 A163658 A163659

Keyword

nonn

Author

Juri-Stepan Gerasimov, Aug 02 2009

Extensions

35 replaced by 36 - R. J. Mathar, Aug 06 2009

Status

approved