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A073156 Main diagonal sequence of triangle A073153. 4
1, 2, 9, 36, 156, 698, 3210, 15080, 72060, 349184, 1711869, 8475494, 42318018, 212843826, 1077391794, 5484472880, 28058940086, 144195777552, 744017466318, 3852968380624, 20019113126120, 104329129258596, 545214946753377 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..22.

FORMULA

Convolution of sequence A073155: a(n)=sum{k=0..n} A073155(k)* A073155(n-k).

G.f.: 1/4*(1-(1-4*x*(1+x)^2)^(1/2))^2/x^2/(1+x)^4. - Vladeta Jovovic, Oct 10 2003

CROSSREFS

Cf. A073153, A073155, A073157.

Sequence in context: A121769 A006782 A150968 * A150969 A150970 A150971

Adjacent sequences:  A073153 A073154 A073155 * A073157 A073158 A073159

KEYWORD

easy,nonn

AUTHOR

Paul D. Hanna, Jul 29 2002

EXTENSIONS

More terms from Vladeta Jovovic, Oct 10 2003

STATUS

approved

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Last modified March 19 17:21 EDT 2019. Contains 321330 sequences. (Running on oeis4.)