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 A128413 Inverse of number triangle A128412. 3
 1, 2, 1, 12, 8, 1, 80, 60, 12, 1, 560, 448, 112, 16, 1, 4032, 3360, 960, 180, 20, 1, 29568, 25344, 7920, 1760, 264, 24, 1, 219648, 192192, 64064, 16016, 2912, 364, 28, 1, 1647360, 1464320, 512512, 139776, 29120, 4480, 480, 32, 1, 12446720 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS First column is A069723. LINKS Table of n, a(n) for n=0..45. FORMULA Number triangle T(n,k)=if(k=0,2^n*(C(2n,n)/2+0^n/2),2^(n-k)*C(2n,n-k)); Column k has g.f. if(k=0,4x/(sqrt(1-8x)(1-sqrt(1-8x))),(1/sqrt(1-8x))*((1-4x-sqrt(1-8x))/(8x))^k); EXAMPLE Triangle begins 1, 2, 1, 12, 8, 1, 80, 60, 12, 1, 560, 448, 112, 16, 1, 4032, 3360, 960, 180, 20, 1, 29568, 25344, 7920, 1760, 264, 24, 1, 219648, 192192, 64064, 16016, 2912, 364, 28, 1 CROSSREFS Cf. A128417. Sequence in context: A257635 A085752 A074966 * A058843 A343861 A130559 Adjacent sequences: A128410 A128411 A128412 * A128414 A128415 A128416 KEYWORD easy,nonn,tabl AUTHOR Paul Barry, Mar 02 2007 STATUS approved

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Last modified June 8 08:19 EDT 2023. Contains 363157 sequences. (Running on oeis4.)