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A117448 Diagonal sums of number triangle A117446. 1
1, 0, 1, 1, 1, -1, 2, -1, 2, 0, 2, -2, 3, -2, 3, -1, 3, -3, 4, -3, 4, -2, 4, -4, 5, -4, 5, -3, 5, -5, 6, -5, 6, -4, 6, -6, 7, -6, 7, -5, 7, -7, 8, -7, 8, -6, 8, -8, 9, -8, 9, -7, 9, -9, 10, -9, 10, -8, 10, -10, 11, -10, 11, -9, 11, -11, 12, -11, 12, -10, 12, -12, 13, -12, 13, -11, 13, -13 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,7

LINKS

Table of n, a(n) for n=0..77.

FORMULA

a(n)=sum{k=0..floor(n/2), C(L(k/3),n-2k)}, where L(j/p) is the Legendre symbol of j and p.

CROSSREFS

Sequence in context: A048272 A112329 A325033 * A093321 A302015 A046144

Adjacent sequences:  A117445 A117446 A117447 * A117449 A117450 A117451

KEYWORD

easy,sign

AUTHOR

Paul Barry, Mar 16 2006

STATUS

approved

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Last modified June 19 13:11 EDT 2019. Contains 324222 sequences. (Running on oeis4.)