Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #10 Aug 29 2021 18:57:06
%S 6,10,15,18,24,26,27,39,42,42,45,50,60,63,66,65,70,74,75,90,91,96,99,
%T 100,105,111,114,114,122,120,125,135,140,146,150,147,162,160,165,168,
%U 170,171,170,175,183,186,185,190,204,210,219,225,224,234,231,231,242,238,243,250
%N a(n) is the n-th triprime (A014612) minus its central prime factor.
%F a(n) = A014612(n) - A162361(n).
%e a(1) = 6 = 2*2*2 - 2;
%e a(2) = 10 = 2*2*3 - 2;
%e a(3) = 15 = 2*3*3 - 3;
%e a(4) = 18 = 2*2*5 - 2;
%e a(5) = 24 = 3*3*3 - 3.
%Y Cf. A014612, A162361.
%K nonn,less
%O 1,1
%A _Juri-Stepan Gerasimov_, Jul 12 2009
%E Definition reformulated, a(11), a(38) etc. corrected by _R. J. Mathar_, Jul 16 2009