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A052115
Number of nonnegative integer pairs (i,j) with binomial(i+r,r) + binomial(j+r,r) <= binomial(n+r,r), r=2.
3
0, 1, 4, 8, 13, 22, 30, 41, 52, 66, 83, 98, 117, 135, 158, 183, 205, 232, 259, 288, 322, 351, 390, 422, 459, 498, 536, 585, 624, 669, 715, 762, 815, 863, 916, 975, 1030, 1088, 1141, 1208, 1272, 1333, 1398, 1460, 1535, 1606, 1677, 1749, 1824, 1901
OFFSET
0,3
PROG
(PARI) a(n) = {nb = 0; for (i=0, n, for (j=0, n, if (binomial(i+2, 2) + binomial(j+2, 2) <= binomial(n+2, 2), nb++); ); ); return (nb); } \\ Michel Marcus, Jun 10 2013
CROSSREFS
KEYWORD
nonn
AUTHOR
Klaus Strassburger (strass(AT)ddfi.uni-duesseldorf.de), Jan 21 2000
STATUS
approved