The OEIS is supported by the many generous donors to the OEIS Foundation.

 Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 59th year, we have over 358,000 sequences, and we’ve crossed 10,300 citations (which often say “discovered thanks to the OEIS”). Other ways to Give
 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A176408 a(n) = (n+1)*(a(n-1) +a(n-2)) 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(n-1)+s(n-2)), n>1, the other being A006347. s(n) = a*a(n) + b* A006347(n+1). s(n) = 1/2*(b-2*a)(n+2)! +(3*a-b)*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*9-24=3, a(3)= 3*44-120=12, a(4)= 3*265-720=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

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

Last modified December 2 23:09 EST 2022. Contains 358510 sequences. (Running on oeis4.)