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 A275328 Triangle read by rows, Riordan array (1, (1+x/(1-4*x^2))/sqrt(1-4*x^2). 2
 1, 0, 1, 0, 2, 1, 0, 6, 4, 1, 0, 6, 16, 6, 1, 0, 30, 36, 30, 8, 1, 0, 20, 120, 98, 48, 10, 1, 0, 140, 232, 342, 200, 70, 12, 1, 0, 70, 756, 924, 784, 350, 96, 14, 1, 0, 630, 1300, 2856, 2576, 1550, 556, 126, 16, 1 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 0,5 LINKS EXAMPLE Table starts: [n] [k=0,1,2,...] row sum [0], [1], 1 [1], [0, 1], 1 [2], [0, 2, 1], 3 [3], [0, 6, 4, 1], 11 [4], [0, 6, 16, 6, 1], 29 [5], [0, 30, 36, 30, 8, 1], 105 [6], [0, 20, 120, 98, 48, 10, 1], 297 [7], [0, 140, 232, 342, 200, 70, 12, 1], 997 [8], [0, 70, 756, 924, 784, 350, 96, 14, 1], 2995 [9], [0, 630, 1300, 2856, 2576, 1550, 556, 126, 16, 1], 9611 MAPLE S := proc(n, k) option remember; local sf: if n = 0 then return n^k fi; sf := n -> n!/iquo(n, 2)!^2; add(sf(i)*S(n-1, k-i), i=1..k-n+1) end: A275328 := (n, k) -> S(k, n): seq(seq(A275328(n, k), k=0..n), n=0..8); MATHEMATICA (* The function RiordanArray is defined in A256893. *) RiordanArray[1&, (1+#/(1-4#^2))/Sqrt[1-4#^2]&, 10] // Flatten (* Jean-François Alcover, Jul 16 2019 *) PROG (Sage) # Function riordan_array defined in A256893. riordan_array(1, (1+x/(1-4*x^2))/sqrt(1-4*x^2), 10) CROSSREFS Cf. A056040 (column 1), A275327. Sequence in context: A301924 A262071 A011312 * A147720 A205813 A127631 Adjacent sequences:  A275325 A275326 A275327 * A275329 A275330 A275331 KEYWORD nonn,tabl,changed AUTHOR Peter Luschny, Aug 19 2016 STATUS approved

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Last modified July 18 07:05 EDT 2019. Contains 325134 sequences. (Running on oeis4.)