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 A247642 Triangle read by rows: T(n,2k+1) = T(n-1,2k-1)+T(n-1,2k), T(n,2k) = T(n-1,2k-2)+2T(n-1,2k-1)+T(n-1,2k). 1
 1, 1, 1, 1, 1, 1, 4, 2, 1, 1, 1, 7, 5, 9, 3, 1, 1, 1, 10, 8, 26, 14, 16, 4, 1, 1, 1, 13, 11, 52, 34, 70, 30, 25, 5, 1, 1, 1, 16, 14, 87, 63, 190, 104, 155, 55, 36, 6, 1, 1, 1, 19, 17, 131, 101, 403, 253, 553, 259, 301, 91, 49, 7, 1, 1, 1, 22, 20, 184 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,7 LINKS Johann Cigler, Some remarks and conjectures related to lattice paths in strips along the x-axis, arXiv:1501.04750 [math.CO], 2015-2016. EXAMPLE Triangle begins: 1 1 1 1 1 1 4 2 1 1 1 7 5 9 3 1 1 1 10 8 26 14 16 4 1 1 1 13 11 52 34 70 30 25 5 1 ... MAPLE A247642 := proc(n, k) option remember; if k < 0 or k > 2*n then return 0; elif k = 0 then return 1 ; end if; if type(k, 'odd') then procname(n-1, k-2)+procname(n-1, k-1) ; else procname(n-1, k-2)+2*procname(n-1, k-1)+procname(n-1, k) ; end if; end proc: # R. J. Mathar, Oct 25 2014 MATHEMATICA T[_, 0] = 1; T[n_, k_] /; 0 <= k <= 2n := T[n, k] = If[OddQ[k], T[n-1, k-2] + T[n-1, k-1], T[n-1, k-2] + 2*T[n-1, k-1] + T[n-1, k]]; T[_, _] = 0; Table[T[n, k], {n, 0, 8}, {k, 0, 2n}] // Flatten (* Jean-François Alcover, Dec 03 2017 *) CROSSREFS Cf. A000244 (row sums). Sequence in context: A303599 A068930 A204815 * A144260 A097526 A051149 Adjacent sequences: A247639 A247640 A247641 * A247643 A247644 A247645 KEYWORD nonn,tabf AUTHOR N. J. A. Sloane, Sep 23 2014 STATUS approved

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Last modified February 5 03:48 EST 2023. Contains 360082 sequences. (Running on oeis4.)