A073686 Group the composite numbers so that the sum of each group is a prime; sequence gives sum of terms in each group.

37, 41, 97, 983, 113, 307, 131, 137, 367, 653, 541, 383, 199, 311, 547, 229, 233, 2293, 281, 5689, 1511, 4349, 439, 443, 449, 1381, 4159, 769, 1571, 2441, 557, 2281, 3253, 2137, 1567, 4877, 9439, 1103, 1487, 751, 6977, 1201, 2843, 823, 827, 9413, 1777

Offset

1,1

Links

Table of n, a(n) for n=1..47.

Example

The first groups are: (4, 6, 8, 9, 10), (12, 14, 15), (16, 18, 20, 21, 22), (24, 25, 26, 27, 28, 30, 32, 33, 34, 35, 36, 38, 39, 40, 42, 44, 45, 46, 48, 49, 50, 51, 52, 54, 55), ..., so sequence begins: 37, 41, ...

Mathematica

t1 = Rest[Select[Range[450], ! PrimeQ[#] &]]; t = {}; s = 0; Do[s += i; If[PrimeQ[s], AppendTo[t, s]; s = 0], {i, t1}]; t (* Jayanta Basu, Jul 07 2013 *)

Crossrefs

Cf. A002808, A073685, A073687.

Sequence in context: A288618 A090263 A033225 * A176926 A217411 A155849

Adjacent sequences: A073683 A073684 A073685 * A073687 A073688 A073689

Keyword

nonn

Author

Amarnath Murthy, Aug 11 2002

Extensions

More terms from Lior Manor, Aug 13 2002

Status

approved