A140235 Partial sum of non-semiprimes A100959.

1, 3, 6, 11, 18, 26, 37, 49, 62, 78, 95, 113, 132, 152, 175, 199, 226, 254, 283, 313, 344, 376, 412, 449, 489, 530, 572, 615, 659, 704, 751, 799, 849, 901, 954, 1008, 1064, 1123, 1183, 1244, 1307, 1371, 1437, 1504, 1572, 1642, 1713, 1785, 1858, 1933, 2009

Offset: 1

Author

Jonathan Vos Post, May 13 2008

Keywords

• easy
• nonn

Comments

This is to semiprimes A001358 as A051352 is to primes A000040. Equivalently, this is to non-semiprimes A100959 as A051349 is to nonprimes A018252.

Examples

			a(5) = 18 = 1 + 2 + 3 + 5 + 7.
		

Crossrefs

Cf. A000217, A001358, A018252, A034387, A051349, A051352, A062198, A072000, A100959, A140234.

Programs

Mathematica

Accumulate[Select[Range[100],PrimeOmega[#]!=2&]] (* Harvey P. Dale, Aug 22 2021 *)

Formula

a(n) = Sum{k=1..n} A100959(k).

Extensions

Corrected and edited by Giovanni Resta, Jun 20 2016