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 #8 Aug 08 2015 09:07:04
%S 1,2,6,10,17,24,34,44,57,70,86,102,121,140,162,184,209,234,262,290,
%T 321,352,386,420,457,494,534,574,617,660,706,752,801,850,902,954,1009,
%U 1064,1122,1180
%N Row sums of triangle in A204028.
%H <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (2,0,-2,1).
%F G.f.: (1+2*x^2)/((1+x)*(1-x)^3)).
%F a(2*n) = A056109(n).
%F a(2*n+1) = A049450(n+1) = 2*A000326(n+1).
%F a(n) = 2*a(n-1) - 2*a(n-3) + a(n-4), a(0) = 1, a(1) = 2, a(2) = 6, a(3) = 10.
%e Triangle in A204028 begins:
%e 1;............................sum = 1
%e 1, 1;.........................sum = 2
%e 1, 4, 1;......................sum = 6
%e 1, 4, 4, 1;...................sum = 10
%e 1, 4, 7, 4, 1;................sum = 17
%e 1, 4, 7, 7, 4, 1;.............sum = 24
%e 1, 4, 7, 10, 7, 4, 1;.........sum = 34
%e 1, 4, 7, 10, 10, 7, 4, 1;.....sum = 44
%Y Cf. A056109, A049450, A204028.
%K easy,nonn
%O 0,2
%A _Philippe Deléham_, Feb 25 2014
%E Corrected by _R. J. Mathar_, Aug 08 2015