A109934 Composite numbers which are not the sum of two distinct primes.

4, 6, 27, 35, 51, 57, 65, 77, 87, 93, 95, 117, 119, 121, 123, 125, 135, 143, 145, 147, 155, 161, 171, 177, 185, 187, 189, 203, 205, 207, 209, 215, 217, 219, 221, 237, 245, 247, 249, 255, 261, 267, 275, 287, 289, 291, 297, 299, 301, 303, 305, 321, 323, 325, 327

Offset

1,1

Comments

Perhaps there are no even terms > 6.

Links

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

Mathematica

f[n_] := (p = 0; pn = PrimePi[n];
Do[ If[n == Prime[i] + Prime[k], p = p + 1; If[p > 2, Break[]]], {i, 1, pn},
{k, i+1, pn}]; p );
Select[Range[2, 400], ! PrimeQ[#] && f[#] == 0 & ] (* Jean-François Alcover, Mar 07 2011 *)

Crossrefs

Cf. A025583.

Sequence in context: A074120 A054265 A105409 * A068321 A349647 A012896

Adjacent sequences: A109931 A109932 A109933 * A109935 A109936 A109937

Keyword

nonn

Author

Amarnath Murthy, Jul 19 2005

Status

approved