A133661 No sum of 2 or more terms equals a prime, terms alternate parity and there are no primes in the list.

1, 8, 25, 86, 209, 472, 25719, 238350, 41931245, 14426603100

Offset: 1

Author

Randy L. Ekl, Dec 28 2007

Keywords

• more
• nonn

Comments

a(10) > 263811880. - Robert G. Wilson v, Jan 01 2008

Examples

			25 is a term, because 25 is odd (previous term was even), 25 is composite and 25+1, 25+8 and 25+8+1 are all composite.
		

Crossrefs

Cf. A052349, A133660.

Programs

Mathematica

(* first do *) Needs["Combinatorica`"] (* then *) lst = {1, 8}; g[k_] := Block[{j = 1, l = 2^Length@lst}, While[j < l && !PrimeQ[Plus @@ NthSubset[j, lst] + k], j++ ]; If[j == l, False, True]]; f[n_] := Block[{k = lst[[ -1]] + 1}, While[PrimeQ@k || g[k] == True, k++; k++ ]; AppendTo[lst, k]; k]; Do[ Print@ f@ n, {n, 10}] (* Robert G. Wilson v, Jan 01 2008 *)

Extensions

a(9) from Robert G. Wilson v, Jan 01 2008

a(10) from Donovan Johnson, Feb 15 2008