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A187012 Antidiagonal sums of A103516. 2

%I

%S 1,2,5,4,8,6,11,8,14,10,17,12,20,14,23,16,26,18,29,20,32,22,35,24,38,

%T 26,41,28,44,30,47,32,50,34,53,36,56,38,59,40,62,42,65,44,68,46,71,48,

%U 74,50,77,52,80,54,83,56,86,58,89,60,92,62,95,64

%N Antidiagonal sums of A103516.

%C This sequence differs from A081556 at least for n=24 (see comment about n=24 in A081556).

%H Vincenzo Librandi, <a href="/A187012/b187012.txt">Table of n, a(n) for n = 2..1000</a>

%F a(n) = sum{k=0..floor(n/2), 0^(k(n-2k))*(n-k+1)}. - _Paul Barry_, Aug 30 2013

%F G.f. : x^2*(1+2*x+3*x^2-x^4)/((1-x)^2*(1+x)^2).

%F a(n) = A080512(n) - 1 for n>2.

%t CoefficientList[Series[(1 + 2 x + 3 x^2 - x^4)/((1 - x)^2 (1 + x)^2), {x, 0, 40}], x] (* _Vincenzo Librandi_, Jun 24 2014 *)

%o (PARI) a(n) = sum(k=0, n\2, 0^(k*(n-2*k))*(n-k+1)); \\ _Michel Marcus_, Aug 30 2013

%K nonn,easy

%O 2,2

%A _Michel Marcus_, Aug 30 2013

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Last modified March 8 11:10 EST 2021. Contains 341948 sequences. (Running on oeis4.)