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 A238374 Row sums of triangle in A204026. 0

%I

%S 1,2,4,6,9,12,17,22,30,38,51,64,85,106,140,174,229,284,373,462,606,

%T 750,983,1216,1593,1970,2580,3190,4177,5164,6761,8358,10942,13526,

%U 17707,21888,28653,35418,46364,57310,75021,92732,121389,150046,196414,242782

%N Row sums of triangle in A204026.

%H <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (1,1,-1,1,-1).

%F G.f.: (1+x)*(1+x^2)/((1-x^2-x^4)*(1-x)).

%F a(n) = a(n-1) + a(n-2) - a(n-3) + a(n-4) - a(n-5), a(0) = 1, a(1) = 2, a(2) = 4, a(3) = 6, a(4) = 9.

%F a(2*n) = A157728(n+5) = A000045(n+5) - 4.

%F a(2*n+1) = 2*A001911(n+1) = 2*A000045(n+4) - 4.

%e Triangle in A204026 begins:

%e 1;.........................sum = 1

%e 1, 1;......................sum = 2

%e 1, 2, 1;...................sum = 4

%e 1, 2, 2, 1;................sum = 6

%e 1, 2, 3, 2, 1;.............sum = 9

%e 1, 2, 3, 3, 2, 1;..........sum = 12

%e 1, 2, 3, 5, 3, 2, 1;.......sum = 17

%e 1, 2, 3, 5, 5, 3, 2, 1;....sum = 22

%e 1, 2, 3, 5, 8, 5, 3, 2, 1;.sum = 30

%t LinearRecurrence[{1,1,-1,1,-1},{1,2,4,6,9},50] (* _Harvey P. Dale_, Feb 24 2018 *)

%Y Cf. A000045, A001911, A157728, A204026

%K easy,nonn

%O 0,2

%A _Philippe DelĂ©ham_, Feb 25 2014

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Last modified January 20 05:45 EST 2020. Contains 331067 sequences. (Running on oeis4.)