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A110326 Diagonal sums of triangle A110324. 2
1, -1, -3, -2, -11, -3, -23, -4, -39, -5, -59, -6, -83, -7, -111, -8, -143, -9, -179, -10, -219, -11, -263, -12, -311, -13, -363, -14, -419, -15, -479, -16, -543, -17, -611, -18, -683, -19, -759, -20, -839, -21, -923, -22, -1011, -23, -1103, -24, -1199, -25, -1299, -26, -1403, -27, -1511, -28, -1623, -29, -1739 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Table of n, a(n) for n=0..58.

Index entries for linear recurrences with constant coefficients, signature (0,3,0,-3,0,1).

FORMULA

G.f.: (1-x-6x^2+x^3+x^4)/((1+x)^3(1-x)^3); a(n)=3a(n-2)-3a(n-4)+a(n-6); a(n)=-(n^2+3n-1)/4-(n^2+n-3)(-1)^n/4.

CROSSREFS

Sequence in context: A215598 A322603 A152177 * A112061 A238398 A065014

Adjacent sequences:  A110323 A110324 A110325 * A110327 A110328 A110329

KEYWORD

easy,sign

AUTHOR

Paul Barry, Jul 20 2005

STATUS

approved

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Last modified June 14 14:07 EDT 2021. Contains 345025 sequences. (Running on oeis4.)