

A249310


Expansion of x*(1+7*x6*x^3)/(18*x^2+6*x^4).


4



1, 7, 8, 50, 58, 358, 416, 2564, 2980, 18364, 21344, 131528, 152872, 942040, 1094912, 6747152, 7842064, 48324976, 56167040, 346116896, 402283936, 2478985312, 2881269248, 17755181120, 20636450368, 127167537088, 147803987456, 910809209984, 1058613197440
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OFFSET

1,2


COMMENTS

It seems that this is also the first row of the spectral array W(sqrt(10)2).
It also seems that, for all k>0, the first row of W(sqrt(k^2+1)k+1) has a generating function of the form x*(1+(2*k+1)*x2*k*x^3)/(1(2*k+2)*x^2+2*k*x^4).


LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..1000
A. Fraenkel and C. Kimberling, Generalized Wythoff arrays, shuffles and interspersions, Discrete Mathematics 126 (1994) 137149.
Index entries for linear recurrences with constant coefficients, signature (0,8,0,6).


MATHEMATICA

CoefficientList[Series[(1 + 7 x  6 x^3)/(1  8 x^2 + 6 x^4), {x, 0, 40}], x] (* Vincenzo Librandi, Oct 25 2014 *)


PROG

(PARI) Vec((1+7*x6*x^3)/(18*x^2+6*x^4) + O(x^100))


CROSSREFS

Cf. A007068 (k=1), A022165 (k=2), A249311 (k=4), A249312 (k=5), A249313 (k=6).
Sequence in context: A116554 A038274 A201919 * A094556 A249329 A041023
Adjacent sequences: A249307 A249308 A249309 * A249311 A249312 A249313


KEYWORD

nonn,easy


AUTHOR

Colin Barker, Oct 25 2014


STATUS

approved



