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 A137219 a(n) = (A126086(n) - 3*A001850(n) + 2)/6. 3
 1, 62, 2649, 116360, 5364701, 256452714, 12582472897, 629389744448, 31955247002601, 1641724953315062, 85159811841234857, 4452782349569991736, 234393562418967430389, 12409423916979629786322, 660253088667210584565249 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS FORMULA a(n) = Sum(binomial(binomial(m,n),3)/2^(m+1),m=0..infinity). MAPLE A126086 := proc(n) local x, y, z ; coeftayl(coeftayl(coeftayl(1/(1-x-y-z-x*y-x*z-y*z-x*y*z), z=0, n), y=0, n), x=0, n) ; end: A001850 := proc(n) local k ; add(binomial(n, k)*binomial(n+k, k), k=0..n) ; end: A137219 := proc(n) (A126086(n)-3*A001850(n)+2)/6 ; end: seq(A137219(n), n=1..30) ; # R. J. Mathar, Apr 01 2008 CROSSREFS Cf. A047665, A137220. Sequence in context: A017725 A092709 A308436 * A065991 A206833 A206841 Adjacent sequences:  A137216 A137217 A137218 * A137220 A137221 A137222 KEYWORD easy,nonn AUTHOR Vladeta Jovovic, Mar 06 2008, Mar 16 2008 EXTENSIONS More terms from R. J. Mathar, Apr 01 2008 STATUS approved

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Last modified March 29 17:23 EDT 2020. Contains 333116 sequences. (Running on oeis4.)