A284206 Tenth column of Euler's difference table in A068106.
0, 0, 0, 0, 0, 0, 0, 0, 362880, 3265920, 33022080, 369774720, 4536362880, 60451816320, 869007242880, 13397819541120, 220448163358080, 3854801333416320, 71370457471716480, 1394586705296776320, 28676809138124407680, 618948032364173877120
Offset: 1
Keywords
Examples
a(13)=4536362880 since this is the number of permutations in S13 that avoid substrings {1(10),2(11),3(12),4(13)}.
Links
- Enrique Navarrete, Generalized K-Shift Forbidden Substrings in Permutations, arXiv:1610.06217 [math.CO], 2016.
Programs
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Mathematica
Table[Sum[(-1)^j*Binomial[n - 9, j]*(n - j)!, {j, 0, n - 9}], {n, 22}] (* Michael De Vlieger, Apr 03 2017 *)
Formula
For n>=10: a(n) = Sum_{j=0..n-9} (-1)^j*binomial(n-9,j)*(n-j)!.
Note a(n)/n! ~ 1/e.
Comments