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URL: https://oeis.org/A194722

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A194722
Number of n-ary words beginning with the first character of the alphabet, that can be built by inserting ten doublets into the initially empty word.
2
0, 1, 92378, 19319845, 560198962, 6507351113, 44731364266, 218878998733, 844131474530, 2730108129937, 7711583225338, 19564269083381, 45486599105938, 98378219490265, 200201768681162, 386776488742813, 714420272913346, 1268930908616993, 2177477525153050
OFFSET
0,3
LINKS
FORMULA
G.f.: x * (1 +92368*x +18396110*x^2 +371157402*x^3 +1763669368*x^4 +2567824154*x^5 +1206169122*x^6 +163325950*x^7 +4293143*x^8 +4862*x^9) / (x-1)^10.
a(0) = 0, a(n) = 1 +(18 +(152 +(798 +(2907 +(7752 +(15504 +(23256 +(25194 +16796*(n-1)) *(n-1)) *(n-1)) *(n-1)) *(n-1)) *(n-1)) *(n-1)) * (n-1)) * (n-1) for n>0.
EXAMPLE
a(1) = 1: a^20 (with 1-ary alphabet {a}).
MAPLE
a:= n-> `if`(n=0, 0, (x-> 1+(18+(152+(798+(2907+(7752+(15504+(23256+
(25194+16796*x)*x)*x)*x)*x)*x)*x)*x)*x)(n-1)):
seq(a(n), n=0..30);
CROSSREFS
Row n=10 of A183134.
Sequence in context: A116122 A116134 A318631 * A140932 A208623 A294857
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Sep 02 2011
STATUS
approved