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A171575 n-th noncomposite number plus n-th even nonprime number. 0

%I #10 Mar 08 2018 12:05:05

%S 1,6,9,13,17,23,27,33,37,43,51,55,63,69,73,79,87,95,99,107,113,117,

%T 125,131,139,149,155,159,165,169,175,191,197,205,209,221,225,233,241,

%U 247,255,263,267,279,283,289,293,307,321,327,331,337,345,349,361,369,377

%N n-th noncomposite number plus n-th even nonprime number.

%F a(n) = A008578(n) + A163300(n).

%e a(1) = 1 + 0 = 1, a(2) = 2 + 4 = 6, a(3) = 3 + 6 = 9.

%t Module[{nc=Select[Range[300],!CompositeQ[#]&],len},len=Length[nc];Join[ {1},Rest[Total/@Thread[{nc,Range[2,2len,2]}]]]] (* _Harvey P. Dale_, Mar 08 2018 *)

%Y Cf. A008578(the noncomposite numbers), A163300(the even nonprime numbers).

%K nonn

%O 1,2

%A _Juri-Stepan Gerasimov_, Dec 12 2009

%E Entries checked by _R. J. Mathar_, May 23 2010

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