

A176408


a(n) = (n+1)*(a(n1) +a(n2)) n>1, a(0)=1,a(1)=0


6



1, 0, 3, 12, 75, 522, 4179, 37608, 376083, 4136910, 49642923, 645357996, 9035011947, 135525179202, 2168402867235, 36862848742992, 663531277373859, 12607094270103318
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

0,3


COMMENTS

a(n) is one of two "basis" sequences for sequences of the form s(0)=a,s(1)=b,s(n)=(n+1)(s(n1)+s(n2)), n>1, the other being A006347.
s(n) = a*a(n) + b* A006347(n+1).
s(n) = 1/2*(b2*a)(n+2)! +(3*ab)*floor(((n+2)!+1)/e).


LINKS

Indranil Ghosh, Table of n, a(n) for n = 0..447
Michael Wallner, A bijection of plane increasing trees with relaxed binary trees of right height at most one, arXiv:1706.07163 [math.CO], 2017, Table 2 on p. 13.


FORMULA

a(n) = 3*floor(((n+2)!+1)/e)  (n+2)!.
a(n) = 3* A000166(n+1)  (n+2)!, where A000166 are the subfactorial numbers.


EXAMPLE

a(2)= 3*924=3, a(3)= 3*44120=12, a(4)= 3*265720=75, ...


MAPLE

seq(3*floor(((n+2)!+1)/E)  (n+2)!, n=1..20);


CROSSREFS

Cf. A000166, A006347.
Sequence in context: A317184 A342599 A291951 * A238630 A247330 A168366
Adjacent sequences: A176405 A176406 A176407 * A176409 A176410 A176411


KEYWORD

nonn


AUTHOR

Gary Detlefs, Apr 16 2010


EXTENSIONS

Data section corrected by Indranil Ghosh, Feb 15 2017


STATUS

approved



