login

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 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A211369
Array read by antidiagonals: T(m,n) = m*(m+n-1)! + Sum( n <= i <= m+n-2 ) i!
2
1, 2, 5, 6, 14, 21, 24, 54, 80, 105, 120, 264, 390, 512, 633, 720, 1560, 2304, 3030, 3752, 4473, 5040, 10800, 15960, 21024, 26070, 31112, 36153, 40320, 85680, 126720, 167160, 207504, 247830, 288152, 328473, 362880, 766080, 1134000
OFFSET
1,2
COMMENTS
Index numbers (compare A055089) of transpositions.
LINKS
Tilman Piesk, Arrays of permutations (Wikiversity)
FORMULA
T(m,1) = A001563(m) + A007489(m-1). - R. J. Mathar, May 11 2013
EXAMPLE
T(3,2) = 3*4! + Sum( 2 <= i <= 3 ) i!
= 3*4! + 2! + 3!
= 3*24 + 2 + 6 = 80.
The array starts:
1, 2, 6, 24, 120,...
5, 14, 54, 264, 1560,...
21, 80, 390, 2304, 15960,...
105, 512, 3030, 21024,167160,...
633, 3752, 26070,207504,1860600,...
MAPLE
A211369 := proc(m, n)
m*(m+n-1)!+add(i!, i=n..m+n-2) ;
end proc: # R. J. Mathar, May 10 2013
CROSSREFS
Cf. A055089, A000142 (row 1), A052649 (row 2)
Sequence in context: A191229 A191120 A245540 * A006596 A000092 A100630
KEYWORD
nonn,tabl
AUTHOR
Tilman Piesk, Jul 07 2012
STATUS
approved