A133659 Primes that are the sum of three consecutive primes as well as the sum of three consecutive composite numbers.

23, 31, 41, 59, 71, 109, 131, 199, 211, 251, 269, 311, 487, 503, 701, 829, 941, 1049, 1061, 1151, 1229, 1381, 1511, 1931, 2129, 2179, 2251, 2269, 2393, 2579, 2971, 3041, 3271, 3329, 3581, 3851, 3889, 3911, 4289, 4451, 4481, 4679, 4987, 4999

Offset

1,1

Links

R. J. Mathar, Table of n, a(n) for n=1..287

Formula

Equals A034962 INTERSECT A060328. - R. J. Mathar, Jan 11 2008

Example

a(3) = 41 because 41 = 11+13+17 and 41 = 12+14+15.

Mathematica

a = {}; For[n = 2, n < 10000, n++, If[ ! PrimeQ[n], AppendTo[a, n + Select[Range[n + 1, n + 10], ! PrimeQ[ # ] &][[1]] + Select[Range[n + 1, n + 10], ! PrimeQ[ # ] &][[2]]]]]; b = Table[Prime[i] + Prime[i + 1] + Prime[i + 2], {i, 1, 10000}]; Select[Intersection[a, b], PrimeQ[ # ] &] (* Stefan Steinerberger, Dec 30 2007 *)

Crossrefs

Cf. A034962, A060328.

Sequence in context: A141818 A060328 A034962 * A309354 A240725 A106312

Adjacent sequences: A133656 A133657 A133658 * A133660 A133661 A133662

Keyword

easy,nonn

Author

Randy L. Ekl, Dec 28 2007

Extensions

More terms from Stefan Steinerberger, Dec 30 2007

Status

approved