The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A141754 Secondary diagonal of A139755, the table of q-derangement numbers of type A. 2
 1, 2, 5, 16, 54, 190, 684, 2505, 9291, 34793, 131277, 498312, 1900862, 7280732, 27983141, 107868939, 416869874, 1614609446, 6265869591, 24358231651, 94837442844, 369755864507, 1443420649734, 5641088964709, 22068939198169 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS FORMULA a(n) = [q^n] { ([n+2]_q)! * Sum_{m=0..n+2} (-1)^m * q^(m(m-1)/2) / ([m]_q)! }; here, the q-factorial of n is denoted by ([n]_q)! = Product_{j=1..n} (1-q^j)/(1-q), with ([0]_q)! = 1. PROG (PARI) {a(n)=polcoeff(prod(j=1, n+2, (1-q^j)/(1-q))* sum(k=0, n+2, (-1)^k*q^(k*(k-1)/2)/if(k==0, 1, prod(j=1, k, (1-q^j)/(1-q)))), n, q)} CROSSREFS Cf. A139755, A141753. Sequence in context: A120899 A149960 A149961 * A149962 A149963 A149964 Adjacent sequences:  A141751 A141752 A141753 * A141755 A141756 A141757 KEYWORD nonn AUTHOR Paul D. Hanna, Jul 05 2008 STATUS approved

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

Last modified September 29 11:11 EDT 2020. Contains 337430 sequences. (Running on oeis4.)