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A249101 p(n,1), where p(n,x) is defined in Comments; sum of numbers in row n of the array at A249100. 2
1, 4, 9, 37, 118, 525, 2059, 9934, 44937, 233683, 1177360, 6552069, 35986069, 212891932, 1256487933, 7856137825, 49320239614, 324285063489, 2149133929207, 14796251405278, 102910742502765, 739149552929719, 5370132965554144, 40110161953250937 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

The polynomial p(n,x) is the numerator of the rational function given by f(n,x) = x + (2*n - 1)/f(n-1,x), where f(1,x) = 1.

LINKS

Table of n, a(n) for n=1..24.

EXAMPLE

First 3 rows from A249100:

1

3    1

5    3    1

so that the first 3 terms of A249101 are 1, 4, 9.

MATHEMATICA

z = 11; p[n_, x_] := x + (2 n - 1)/p[n-1, x]; p[1, x_] = 1;

t = Table[Factor[p[n, x]], {n, 1, z}]

u = Numerator[t]; v = u /. x -> 1  (* A249101 *)

CROSSREFS

Cf. A249100.

Sequence in context: A055872 A066924 A251689 * A289157 A149146 A149147

Adjacent sequences:  A249098 A249099 A249100 * A249102 A249103 A249104

KEYWORD

nonn,easy

AUTHOR

Clark Kimberling, Oct 21 2014

STATUS

approved

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Last modified April 1 02:10 EDT 2020. Contains 333153 sequences. (Running on oeis4.)