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A024476 a(n) = s(1)*t(n) + s(2)*t(n-1) + ... + s(k)*t(n+1-k), where k = floor((n+1)/2), s = (Lucas numbers), t = A023533. 1

%I #7 Aug 01 2022 18:43:44

%S 1,0,0,1,3,4,7,0,0,1,3,4,7,11,18,29,47,76,123,1,3,4,7,11,18,29,47,76,

%T 123,199,322,521,843,1364,2208,3574,5782,9356,15138,18,29,47,76,123,

%U 199,322,521,843,1364,2207,3571,5778,9349,15127,24476,39604,64082,103686,167768

%N a(n) = s(1)*t(n) + s(2)*t(n-1) + ... + s(k)*t(n+1-k), where k = floor((n+1)/2), s = (Lucas numbers), t = A023533.

%H G. C. Greubel, <a href="/A024476/b024476.txt">Table of n, a(n) for n = 1..5000</a>

%F a(n) = Sum_{k=1..floor((n+1)/2)} A000032(k) * A023533(n-k+1).

%t A023533[n_]:= A023533[n]= If[Binomial[Floor[Surd[6*n-1,3]]+2, 3]!= n,0,1];

%t A024476[n_]:= A024476[n]= Sum[LucasL[j]*A023533[n-j+1], {j, Floor[(n+1)/2]}];

%t Table[A024476[n], {n, 100}] (* _G. C. Greubel_, Aug 01 2022 *)

%o (Magma)

%o A023533:= func< n | Binomial(Floor((6*n-1)^(1/3)) +2, 3) ne n select 0 else 1 >;

%o [(&+[Lucas(k)*A023533(n+1-k): k in [1..Floor((n+1)/2)]]): n in [1..100]]; // _G. C. Greubel_, Aug 01 2022

%o (SageMath)

%o @CachedFunction

%o def A023533(n): return 0 if (binomial(floor((6*n-1)^(1/3)) +2, 3)!= n) else 1

%o def A024476(n): return sum(lucas_number2(j,1,-1)*A023533(n-j+1) for j in (1..((n+1)//2)))

%o [A024476(n) for n in (1..100)] # _G. C. Greubel_, Aug 01 2022

%Y Cf. A000032, A023533.

%K nonn

%O 1,5

%A _Clark Kimberling_

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Last modified April 25 03:15 EDT 2024. Contains 371964 sequences. (Running on oeis4.)