

A151575


G.f.: (1+x)/(1+x2*x^2).


15



1, 0, 2, 2, 6, 10, 22, 42, 86, 170, 342, 682, 1366, 2730, 5462, 10922, 21846, 43690, 87382, 174762, 349526, 699050, 1398102, 2796202, 5592406, 11184810, 22369622, 44739242, 89478486, 178956970, 357913942, 715827882, 1431655766, 2863311530, 5726623062
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OFFSET

0,3


COMMENTS

Or, g.f. = (1+x)/((1x)*(12*x)).
A signed version of A078008, which is the main entry.
[1, 0, 2, 2, 6, 10, 22, 42, 86,...] = an operator for toothpick sequences. The sequence convolved with A151548 = toothpick sequence A139250. The sequence convolved with A151555 = toothpick sequence A153006.  Gary W. Adamson, May 25 2009


LINKS

Table of n, a(n) for n=0..34.


FORMULA

a(n)=(2+(2)^n)/3 = (1)^n*A078008(n), n>=0. a(n)=2*A077925(n2), n>1.  R. J. Mathar, Jul 08 2009
a(n)= A084247(n+1)/2.  Philippe Deléham, Sep 21 2009
G.f.: 1 + x  x*Q(0), where Q(k) = 1 + 2*x^2  (2*k+3)*x + x*(2*k+1  2*x)/Q(k+1); (continued fraction).  Sergei N. Gladkovskii, Oct 05 2013


CROSSREFS

Sequence in context: A019310 A014113 A078008 * A284462 A262278 A265639
Adjacent sequences: A151572 A151573 A151574 * A151576 A151577 A151578


KEYWORD

sign


AUTHOR

N. J. A. Sloane, May 25 2009, based on a suggestion from Gary W. Adamson


STATUS

approved



