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!)
 A264916 Number of n-ascent sequences of length n with no consecutive repeated letters. 2
 1, 1, 2, 12, 110, 1380, 21931, 422128, 9544164, 247924425, 7276062838, 238094692473, 8595519551905, 339369780700496, 14547197878632067, 672813893127964088, 33396560680565891888, 1770862858604836365591, 99902715110909008145856, 5974701996798223000294793 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS Alois P. Heinz, Table of n, a(n) for n = 0..125 S. Kitaev, J. Remmel, p-Ascent Sequences, arXiv:1503.00914 [math.CO], 2015. FORMULA a(n) = A264909(n,n). a(n) ~ c * n! * d^n / n^(3/2), where d = 3.4022754519536669374151613210346790003... and c = 0.34285335011727623741388891327237... - Vaclav Kotesovec, Aug 14 2017 MAPLE b:= proc(n, k, i, t) option remember; `if`(n<1, 1, add( `if`(j=i, 0, b(n-1, k, j, t+`if`(j>i, 1, 0))), j=0..t+k)) end: a:= n-> b(n-1, n, 0\$2): seq(a(n), n=0..25); MATHEMATICA b[n_, k_, i_, t_] := b[n, k, i, t] = If[n < 1, 1, Sum[If[j == i, 0, b[n - 1, k, j, t + If[j > i, 1, 0]]], {j, 0, t + k}]]; a[n_] := b[n - 1, n, 0, 0]; Table[a[n], {n, 0, 25}] (* Jean-François Alcover, Nov 09 2017, after Alois P. Heinz *) CROSSREFS Main diagonal of A264909. Sequence in context: A217802 A126778 A158832 * A296644 A235860 A317208 Adjacent sequences: A264913 A264914 A264915 * A264917 A264918 A264919 KEYWORD nonn AUTHOR Alois P. Heinz, Nov 28 2015 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 3 08:35 EST 2022. Contains 358515 sequences. (Running on oeis4.)