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 #7 Nov 26 2023 10:58:01
%S 0,1,3,8,21,53,129,305,705,1601,3585,7937,17409,37889,81921,176129,
%T 376833,802817,1703937,3604481,7602177,15990785,33554433,70254593,
%U 146800641,306184193,637534209,1325400065,2751463425,5704253441,11811160065,24427626497,50465865729
%N a(0)=0; thereafter a(n) = (3*n+1)*2^(n-2)+1.
%t Join[{0,1},Table[(3n+1)2^(n-2)+1,{n,40}]] (* _Harvey P. Dale_, Nov 26 2023 *)
%Y Essentially the first column of the triangular array in A151747.
%Y Partial sums of A098156.
%K nonn
%O 0,3
%A _N. J. A. Sloane_, Jan 07 2010
%E Zero prepended by _Harvey P. Dale_, Nov 26 2023