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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A128571 Row 1 of table A128570. 11

%I

%S 1,2,12,114,1440,22368,409248,8585088,202733760,5317663680,

%T 153345634560,4821848409600,164211751261440,6022162697840640,

%U 236652023784960000,9921992082873223680,442138176056374548480,20869300232695599552000,1040210006521640127367680,54600929159270409876879360

%N Row 1 of table A128570.

%H Paul D. Hanna, <a href="/A128571/b128571.txt">Table of n, a(n) for n = 0..200</a>

%F G.f.: A(x) = 1 + 2x*R(x,2)^2, where R(x,2) = 1 + 3*x*R(x,3)^2, R(x,3) = 1 + 4*x*R(x,4)^2, ..., R(x,n) = 1 + (n+1)*x*R(x,n+1)^2, ... and R(x,n) is the g.f. of row n of table A128570.

%F a(n) ~ 4*n*A128318(n)/3. - _Vaclav Kotesovec_, Mar 19 2016

%o (PARI) {a(n)=local(A=1+(n+2)*x);for(j=0,n,A=1+(n+2-j)*x*A^2 +x*O(x^n)); polcoeff(A,n)}

%o for(n=0,25,print1(a(n),", "))

%Y Cf. A128570 (triangle), other rows: A128318, A128572, A128573, A128574, A128575, A128576; A128577 (square of row 0), A128578 (main diagonal), A128579 (antidiagonal sums).

%Y Cf. A268652.

%K nonn

%O 0,2

%A _Paul D. Hanna_, Mar 11 2007

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.

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 2 19:18 EST 2021. Contains 341756 sequences. (Running on oeis4.)