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A094664 Row sums of triangle A094344. 4
1, 1, 2, 7, 38, 286, 2756, 32299, 444998, 7038898, 125620652, 2495811814, 54618201884, 1305184303996, 33812846036552, 943878836768947, 28242424937855558, 901709392642750186, 30597227032818965276, 1099566630423067201234, 41718229482624755005748 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Alois P. Heinz, Table of n, a(n) for n = 0..200

FORMULA

a(n) = Sum_{k = 0..n} A094344(n, k).

From Gary W. Adamson, Jul 26 2011: (Start)

a(n) = upper left term in M^n, a(n+1) =  sum of top row terms in M^n; M = the following infinite square production matrix:

1, 1, 0, 0, 0,...

1, 1, 3, 0, 0,...

1, 1, 1, 5, 0,...

1, 1, 1, 1, 7,...

... (End)

G.f.: 1/(1 - x/(1 - x/(1 - 3*x/(1 - 3*x/(1 - 5*x/(1 - 5*x/(1 - 7*x/(1 - 7*x/(1-...))))))))) (continued fraction). [Paul D. Hanna, Sep 17 2011]

G.f.: 1/U(0) where U(k)= 1 - x*(2*k+1)/(1 - x*(2*k+1)/U(k+1)) ; (continued fraction, 2-step). - Sergei N. Gladkovskii, Oct 15 2012

G.f. A(x) satisfies A(x) = 1 + x*(2*A(x)-A(x)^2) + 2*x^2*A'(x). - Paul D. Hanna, Mar 09 2013

G.f.: 2 - 1/Q(0) where Q(k) =  1 - x*(2*k-1)/(1 - x*(2*k+3)/Q(k+1) ); (continued fraction). - Sergei N. Gladkovskii, Mar 19 2013

G.f.: Q(0)/x - 1/x, where Q(k)= 1 - x*(2*k-1)/(1 - x*(2*k+1)/Q(k+1)); (continued fraction). - Sergei N. Gladkovskii, May 21 2013

G.f.: 2/G(0), where G(k)= 1 + 1/(1 - x*(4*k+2)/(x*(4*k+2) - 1 + x*(4*k+2)/G(k+1))); (continued fraction). - Sergei N. Gladkovskii, May 31 2013

G.f.: G(0)/2/x - 1/x + 2, where G(k)= 1 + 1/(1 - 2*x*(2*k+1)/(2*x*(2*k+1) - 1 + 2*x*(2*k-1)/G(k+1))); (continued fraction). - Sergei N. Gladkovskii, May 31 2013

G.f.: G(0), where G(k)= 1 - x*(2*k+1)/(x*(2*k+1) - 1/(1 - x*(2*k+1)/(x*(2*k+1) - 1/G(k+1) ))); (continued fraction). - Sergei N. Gladkovskii, Aug 07 2013

G.f.: 2 - 1/x - G(0)/x, where G(k)= 2*x - 2*x*k - 1 - x*(2*k-1)/G(k+1) ; (continued fraction). - Sergei N. Gladkovskii, Aug 14 2013

a(n) ~ 2^n * (n-1)! / Pi. - Vaclav Kotesovec, Sep 05 2017

EXAMPLE

a(3) = 7, a(4) = 38, since top row of M^3 = (7, 7, 9, 15) with 38 = (7 + 7 + 9 + 15).

MATHEMATICA

nmax = 20; CoefficientList[Series[1/Fold[(1 - #2/#1) &, 1, Reverse[(2*Range[nmax + 1] - 2*Floor[Range[nmax + 1]/2] - 1)*x]], {x, 0, nmax}], x] (* Vaclav Kotesovec, Sep 05 2017 *)

PROG

(PARI) {a(n)=local(CF=1+x*O(x^n)); for(k=0, n, CF=1/(1-(2*n-2*k+1)*x/(1-(2*n-2*k+1)*x*CF))); polcoeff(CF, n, x)} /* Paul D. Hanna */

(PARI) {a(n)=local(A=1+x); for(i=1, n, A=1+x*(2*A-A^2)+2*x^2*A'+x*O(x^n)); polcoeff(A, n)} \\ Paul D. Hanna, Mar 09 2013

CROSSREFS

Sequence in context: A114160 A145159 A084552 * A001858 A233335 A000366

Adjacent sequences:  A094661 A094662 A094663 * A094665 A094666 A094667

KEYWORD

easy,nonn

AUTHOR

Philippe Deléham, Jun 06 2004

STATUS

approved

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Last modified October 21 08:42 EDT 2018. Contains 316405 sequences. (Running on oeis4.)