This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A124139 #6 Apr 19 2016 01:16:09 %S A124139 1,11,19,23,1,37,29,25,41,25,25,19,67,65,199,397,895,1939,1063,563, %T A124139 305,1303,2413,5575,11983,13169,37729,19087,85225,156469,181271, %U A124139 506611,64489,856651,1381711,419693,2702107,4682701,11077213,369373,2146235,3773413 %N A124139 a(n) = A000265(3*(a(n-1) + a(n-2))/2 + 1) starting at a(1)=1, a(2)=11. %C A124139 A variant of A105801: The highest power of two is recursively removed from 3x/2+1, where x is the sum of the preceding two elements of the sequence. %p A124139 A000265 := proc(n) local a,nshft ; a := 1 ; nshft := n ; while nshft mod 2 = 0 do nshft := nshft/2 ; od: nshft ; end: %p A124139 A124139 := proc(n) option remember ; if n = 1 then 1; elif n = 2 then 11; else A000265(3*(procname(n-1)+procname(n-2))/2 +1) ; fi; end: seq(A124139(n),n=1..60) ; # _R. J. Mathar_, Jul 02 2009 %Y A124139 Cf. A124138. %K A124139 nonn %O A124139 1,2 %A A124139 _Yasutoshi Kohmoto_, Dec 01 2006 %E A124139 Edited and extended by _R. J. Mathar_, Jul 02 2009