A166685 Odd numbers that are the sum of two consecutive nonprimes.

1, 5, 17, 19, 29, 31, 41, 43, 49, 51, 53, 55, 65, 67, 69, 71, 77, 79, 89, 91, 97, 99, 101, 103, 109, 111, 113, 115, 125, 127, 129, 131, 137, 139, 149, 151, 153, 155, 161, 163, 169, 171, 173, 175, 181, 183, 185, 187, 189, 191, 197, 199, 209, 211, 221, 223, 229

Offset

1,2

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Example

a(1)=0(1st nonprime)+1(2nd nonprime)=1(odd);
a(2)=1(2nd nonprime)+4(3rd nonprime)=5(odd).

Mathematica

Select[Total/@Partition[Select[Range[0, 200], !PrimeQ[#]&], 2, 1], OddQ] (* Harvey P. Dale, Mar 07 2020 *)

Crossrefs

Cf. A118134, A141468, A163467.

Sequence in context: A038896 A117382 A191076 * A167915 A019373 A140568

Adjacent sequences: A166682 A166683 A166684 * A166686 A166687 A166688

Keyword

nonn

Author

Juri-Stepan Gerasimov, Oct 18 2009

Extensions

Entries checked by R. J. Mathar, Apr 24 2010

Status

approved