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 A024316 a(n) = s(1)*s(n) + s(2)*s(n-1) + ... + s(k)*s(n+1-k), where k = floor((n+1)/2)), s = A023531. 18
 0, 0, 1, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1, 2, 0, 0, 1, 0, 1, 0, 1, 1, 0, 0, 2, 1, 0, 0, 1, 0, 1, 1, 0, 2, 0, 0, 0, 1, 1, 1, 1, 0, 1, 1, 0, 0, 1, 1, 1, 0, 0, 1, 1, 0, 2, 1, 0, 0, 2, 0, 0, 0, 0, 3, 0, 1, 1, 0, 0, 1, 1, 0, 1, 1, 0, 1 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,28 LINKS Reinhard Zumkeller, Table of n, a(n) for n = 1..10000 FORMULA a(n) = Sum_{j=1..floor((n+1)/2)} A023531(j)*A023531(n-j+1). - G. C. Greubel, Jan 17 2022 MATHEMATICA A023531[n_]:= SquaresR[1, 8n+9]/2; a[n_]:= a[n]= Sum[A023531[j]*A023531[n-j+1], {j, Floor[(n+1)/2]}]; Table[a[n], {n, 110}] (* G. C. Greubel, Jan 17 2022 *) PROG (Haskell) a024316 n = sum \$ take (div (n + 1) 2) \$ zipWith (*) zs \$ reverse zs where zs = take n \$ tail a023531_list -- Reinhard Zumkeller, Feb 14 2015 (Magma) A023531:= func< n | IsIntegral( (Sqrt(8*n+9) - 3)/2 ) select 1 else 0 >; [ (&+[A023531(j)*A023531(n-j+1): j in [1..Floor((n+1)/2)]]) : n in [1..110]]; // G. C. Greubel, Jan 17 2022 (Sage) def A023531(n): if ((sqrt(8*n+9) -3)/2).is_integer(): return 1 else: return 0 [sum( A023531(j)*A023531(n-j+1) for j in (1..floor((n+1)/2)) ) for n in (1..110)] # G. C. Greubel, Jan 17 2022 CROSSREFS Cf. A024312, A024313, A024314, A024315, A024317, A024318, A024319, A024320, A024321, A024322, A024323, A024324, A024325, A024326, A024327. Cf. A023531. Sequence in context: A121454 A025462 A024879 * A345375 A101669 A243067 Adjacent sequences: A024313 A024314 A024315 * A024317 A024318 A024319 KEYWORD nonn AUTHOR Clark Kimberling STATUS approved

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Last modified September 22 13:35 EDT 2023. Contains 365531 sequences. (Running on oeis4.)