A204558 Row sums of the triangle A045975.

1, 6, 45, 120, 325, 630, 1225, 2016, 3321, 4950, 7381, 10296, 14365, 19110, 25425, 32640, 41905, 52326, 65341, 79800, 97461, 116886, 140185, 165600, 195625, 228150, 266085, 306936, 354061, 404550, 462241, 523776, 593505, 667590, 750925, 839160, 937765

Offset

1,2

Comments

a(n) = sum(A045975(n,k): k = 1 .. n);

a(n) = n * (if n even then A035328(n/2) else A005817((n+1)/2)). [Reinhard Zumkeller, Jan 18 2012]

Links

Table of n, a(n) for n=1..37.

Formula

Conjecture: a(n) = (n^2*(-(-1)^n+n^2))/2. G.f.: -x*(x^6 +4*x^5 +31*x^4 +24*x^3 +31*x^2 +4*x +1) / ((x -1)^5*(x +1)^3). - Colin Barker, Apr 02 2013

Prog

(Haskell)
a204558 = sum . a045975_row

Crossrefs

Sequence in context: A006086 A273507 A131513 * A354477 A123141 A122096

Adjacent sequences: A204555 A204556 A204557 * A204559 A204560 A204561

Keyword

nonn

Author

Reinhard Zumkeller, Jan 18 2012

Status

approved