A166037 Numbers that are the sum of 2 successive nonprimes A141468.

1, 5, 10, 14, 17, 19, 22, 26, 29, 31, 34, 38, 41, 43, 46, 49, 51, 53, 55, 58, 62, 65, 67, 69, 71, 74, 77, 79, 82, 86, 89, 91, 94, 97, 99, 101, 103, 106, 109, 111, 113, 115, 118, 122, 125, 127, 129, 131, 134, 137, 139, 142, 146, 149, 151, 153, 155, 158, 161, 163, 166

Offset

1,2

Comments

a(n) = (n-1)-th nonprimes + (n-1)-th composites for n >= 2. a(n) = A018252(n-1) + A002808(n-1) for n >= 2. - Jaroslav Krizek, Dec 13 2009

Links

Harvey P. Dale, Table of n, a(n) for n = 1..10000

Example

a(1) = 0 + 1 =  1;
a(2) = 1 + 4 =  5;
a(3) = 4 + 6 = 11.

Maple

A002808 := proc(n) option remember; if n = 1 then 4; else for a from procname(n-1)+1 do if not isprime(a) then return a; fi; od: fi; end: A141468 := proc(n) if n <= 2 then n-1 ; else A002808(n-2) ; fi; end: A166037 := proc(n) A141468(n)+A141468(n+1) ; end: seq(A166037(n), n=1..120) ; # R. J. Mathar, Oct 10 2009

Mathematica

With[{nn=100}, Join[{1}, Total/@Partition[Complement[Range[nn], Prime[ Range[ PrimePi[ nn]]]], 2, 1]]] (* Harvey P. Dale, Aug 03 2014 *)

Crossrefs

Cf. A001043, A141468.

Cf. A167915 (primes that are the sums of two consecutive composites).

Sequence in context: A313452 A023981 A313453 * A313454 A313455 A313456

Adjacent sequences: A166034 A166035 A166036 * A166038 A166039 A166040

Keyword

nonn

Author

Juri-Stepan Gerasimov, Oct 05 2009

Status

approved