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A194721 Number of n-ary words beginning with the first character of the alphabet, that can be built by inserting nine doublets into the initially empty word. 2
0, 1, 24310, 2699837, 52955950, 464221105, 2561439806, 10466643805, 34648845862, 98156060225, 246643289830, 563506356061, 1191627482750, 2363434581937, 4441172224750, 7969478316605, 13742556531766, 22888430598145, 36972962559062, 58126513174525, 89196318660430 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Alois P. Heinz, Table of n, a(n) for n = 0..1000

FORMULA

G.f.: -x * (1 +24301*x +2481083*x^2 +29532493*x^3 +82769773*x^4 +66140687*x^5 +14462017*x^6 +624055*x^7 +1430*x^8) / (x-1)^9.

a(0) = 0, a(n) = 1 +(16 +(119 +(544 +(1700 +(3808 +(6188 +(7072 +4862 * (n-1)) *(n-1)) *(n-1)) *(n-1)) *(n-1)) *(n-1)) *(n-1)) *(n-1) for n>0.

EXAMPLE

a(1) = 1: a^18 (with 1-ary alphabet {a}).

MAPLE

a:= n-> `if`(n=0, 0, (x-> 1+(16+(119+(544+(1700+(3808+(6188+(7072+4862

                          *x)*x)*x)*x)*x)*x)*x)*x)(n-1)):

seq(a(n), n=0..30);

CROSSREFS

Row n=9 of A183134.

Sequence in context: A078870 A154069 A318630 * A140923 A208622 A294856

Adjacent sequences:  A194718 A194719 A194720 * A194722 A194723 A194724

KEYWORD

nonn

AUTHOR

Alois P. Heinz, Sep 02 2011

STATUS

approved

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Last modified February 21 02:57 EST 2019. Contains 320364 sequences. (Running on oeis4.)