The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Please make a donation to keep the OEIS running. We are now in our 56th year. In the past year we added 10000 new sequences and reached almost 9000 citations (which often say "discovered thanks to the OEIS"). Other ways to donate

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A194719 Number of n-ary words beginning with the first character of the alphabet, that can be built by inserting seven doublets into the initially empty word. 2
 0, 1, 1716, 54573, 492724, 2467137, 8786436, 25066621, 61189668, 133071009, 264735892, 490704621, 858686676, 1432583713, 2295801444, 3554870397, 5343375556, 7826194881, 11204046708, 15718346029, 21656369652, 29356730241, 39215159236, 51690598653, 67311601764 (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+1709*x+42582*x^2+146714*x^3+104077*x^4+13665*x^5+132*x^6) / (x-1)^7. a(0) = 0, a(n) = 1+(12+(65+(208+(429+(572+429*(n-1)) * (n-1)) * (n-1)) * (n-1)) * (n-1)) * (n-1) for n>0. EXAMPLE a(1) = 1: a^14 (with 1-ary alphabet {a}). MAPLE a:= n-> `if`(n=0, 0, (x-> 1+(12+(65+(208+(429+(572+429*x)*x)*x)                           *x)*x)*x)(n-1)): seq(a(n), n=0..30); CROSSREFS Row n=7 of A183134. Sequence in context: A260474 A222343 A318628 * A140910 A208620 A294854 Adjacent sequences:  A194716 A194717 A194718 * A194720 A194721 A194722 KEYWORD nonn AUTHOR Alois P. Heinz, Sep 02 2011 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified November 25 07:58 EST 2020. Contains 338618 sequences. (Running on oeis4.)