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 A113245 a(n) = floor(binomial(2n,2k)/binomial(n,k)). 1
 1, 1, 1, 1, 3, 1, 1, 5, 5, 1, 1, 7, 11, 7, 1, 1, 9, 21, 21, 9, 1, 1, 11, 33, 46, 33, 11, 1, 1, 13, 47, 85, 85, 47, 13, 1, 1, 15, 65, 143, 183, 143, 65, 15, 1, 1, 17, 85, 221, 347, 347, 221, 85, 17, 1, 1, 19, 107, 323, 599, 733, 599, 323, 107, 19, 1, 1, 21, 133, 452, 969, 1399 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 0,5 COMMENTS Row sums of inverse appear to be A000007. LINKS FORMULA Number triangle T(n, k)=if(k<=n, floor(C(2n, 2k)/C(n, k)), 0). EXAMPLE Triangle begins 1; 1, 1; 1, 3, 1; 1, 5, 5, 1; 1, 7, 11, 7, 1; 1, 9, 21, 21, 9, 1; 1, 11, 33, 46, 33, 11, 1; MATHEMATICA Flatten[ Table[ Floor[ Binomial[2n, 2k]/Binomial[n, k]], {n, 0, 11}, {k, 0, n}]] (* Robert G. Wilson v, Oct 21 2005 *) CROSSREFS Even terms are in A111304. Sequence in context: A026615 A026681 A109128 * A103450 A128254 A277930 Adjacent sequences: A113242 A113243 A113244 * A113246 A113247 A113248 KEYWORD easy,nonn,tabl AUTHOR Paul Barry, Oct 20 2005 STATUS approved

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Last modified March 22 18:49 EDT 2023. Contains 361433 sequences. (Running on oeis4.)