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A182017 Row square-sums of triangle A182013. 1
1, 5, 29, 165, 1020, 6606, 44805, 314299, 2266834, 16714004, 125501364, 956725836, 7387322749, 57669478609, 454492588153, 3611698593169, 28911762536992, 232949503809562, 1887883708627582, 15380196764853214, 125893997550676627, 1034945699861044243 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..21.

FORMULA

a(n) = sum(sum(M(i),i=k..n))^2,k=0..n), where the M(n)'s are the Motzkin numbers.

MATHEMATICA

M[n_]:=If[n==0, 1, Coefficient[(1+x+x^2)^(n+1), x^n]/(n+1)]; Table[Sum[Sum[M[i], {i, k, n}]^2, {k, 0, n}], {n, 0, 40}]

PROG

(Maxima) M(n):=coeff(expand((1+x+x^2)^(n+1)), x^n)/(n+1);

makelist(sum(sum(M(i), i, k, n)^2, k, 0, n), n, 0, 20);

CROSSREFS

Cf. A182013.

Sequence in context: A146178 A272751 A015537 * A291017 A141812 A227206

Adjacent sequences:  A182014 A182015 A182016 * A182018 A182019 A182020

KEYWORD

nonn

AUTHOR

Emanuele Munarini, Apr 06 2012

STATUS

approved

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Last modified September 23 12:53 EDT 2020. Contains 337310 sequences. (Running on oeis4.)