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Partial sum of non-semiprimes A100959.
1

%I #7 Aug 22 2021 18:18:51

%S 1,3,6,11,18,26,37,49,62,78,95,113,132,152,175,199,226,254,283,313,

%T 344,376,412,449,489,530,572,615,659,704,751,799,849,901,954,1008,

%U 1064,1123,1183,1244,1307,1371,1437,1504,1572,1642,1713,1785,1858,1933,2009

%N Partial sum of non-semiprimes A100959.

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

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

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

%t Accumulate[Select[Range[100],PrimeOmega[#]!=2&]] (* _Harvey P. Dale_, Aug 22 2021 *)

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

%K easy,nonn

%O 1,2

%A _Jonathan Vos Post_, May 13 2008

%E Corrected and edited by _Giovanni Resta_, Jun 20 2016