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 A260776 Certain directed lattice paths. 2
 1, 5, 60, 1001, 19380, 408595, 9104550, 210905400, 5028168132, 122563178210, 3040594338320, 76520801509425, 1948777701739050, 50129821093933224, 1300611345665798320, 33994757853301868560, 894295618431497324900, 23660280955151412585930, 629143806228348421209768 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS See Dziemianczuk (2014) for precise definition. LINKS Lars Blomberg, Table of n, a(n) for n = 0..100 M. Dziemianczuk, On Directed Lattice Paths With Additional Vertical Steps, arXiv preprint arXiv:1410.5747 [math.CO], 2014. FORMULA See Dziemianczuk (2014) Equation (36b) with N=3. From Peter Bala, Mar 30 2020: (Start) a(n) = (1/n)*C(5*n,2*n-1) for n >= 1. a(n) = 2*Sum_{k = 0..n} C(3*n+k,n+3*k)*C(n+3*k,k)/(n+2*k+1). Cf. A027307(n) = Sum_{k = 0..n} C(2*n+k,n+2*k)*C(n+2*k,k)/(n+k+1) for n >= 1. (End) CROSSREFS Sequence in context: A234528 A277300 A156125 * A128574 A120976 A062980 Adjacent sequences: A260773 A260774 A260775 * A260777 A260778 A260779 KEYWORD nonn,easy AUTHOR N. J. A. Sloane, Jul 30 2015 EXTENSIONS More terms from Lars Blomberg, Aug 01 2015 STATUS approved

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Last modified September 14 09:25 EDT 2024. Contains 375921 sequences. (Running on oeis4.)