The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A126454 Triangle, read by rows, where T(n,k) = C( C(n+2,3) - C(k+2,3) + 2, n-k) for n>=k>=0. 8
 1, 3, 1, 15, 5, 1, 220, 55, 8, 1, 7315, 1330, 153, 12, 1, 435897, 58905, 5456, 351, 17, 1, 40475358, 4187106, 316251, 17296, 703, 23, 1, 5373200880, 437353560, 27285336, 1282975, 45760, 1275, 30, 1, 962889794295, 63140314380, 3295144749, 134153712 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS Amazingly, A126460 = A126445^-1*A126450 = A126450^-1*A126454 = A126454^-1*A126457; and also A126465 = A126450*A126445^-1 = A126454*A126450^-1 = A126457*A126454^-1. LINKS FORMULA T(n,k) = C( n*(n+1)*(n+2)/3! - k*(k+1)*(k+2)/3! + 2, n-k) for n>=k>=0. EXAMPLE Formula: T(n,k) = C( C(n+2,3) - C(k+2,3) + 2, n-k) is illustrated by: T(n=4,k=1) = C( C(6,3) - C(3,3) + 2, n-k) = C(21,3) = 1330; T(n=4,k=2) = C( C(6,3) - C(4,3) + 2, n-k) = C(18,2) = 153; T(n=5,k=2) = C( C(7,3) - C(4,3) + 2, n-k) = C(33,3) = 5456. Triangle begins: 1; 3, 1; 15, 5, 1; 220, 55, 8, 1; 7315, 1330, 153, 12, 1; 435897, 58905, 5456, 351, 17, 1; 40475358, 4187106, 316251, 17296, 703, 23, 1; 5373200880, 437353560, 27285336, 1282975, 45760, 1275, 30, 1; ... MATHEMATICA Table[Binomial[Binomial[n+2, 3]-Binomial[k+2, 3]+2, n-k], {n, 0, 10}, {k, 0, n}]// Flatten (* Harvey P. Dale, Dec 17 2020 *) PROG (PARI) T(n, k)=binomial(n*(n+1)*(n+2)/3!-k*(k+1)*(k+2)/3!+2, n-k) CROSSREFS Columns: A126455, A126456; variants: A126445, A126450, A126457, A107870. Sequence in context: A119301 A293157 A121335 * A293558 A259841 A228540 Adjacent sequences:  A126451 A126452 A126453 * A126455 A126456 A126457 KEYWORD nonn,tabl AUTHOR Paul D. Hanna, Dec 27 2006 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified August 8 16:23 EDT 2022. Contains 356015 sequences. (Running on oeis4.)