This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A061312 #15 Sep 08 2022 08:45:03 %S A061312 0,1,1,4,3,2,18,14,11,9,96,78,64,53,44,600,504,426,362,309,265,4320, %T A061312 3720,3216,2790,2428,2119,1854,35280,30960,27240,24024,21234,18806, %U A061312 16687,14833,322560,287280,256320,229080,205056,183822,165016,148329 %N A061312 Triangle T[n,m]: T[n,-1] = 0; T[0,0] = 0; T[n,0] = n*n!; T[n,m] = T[n,m-1] - T[n-1,m-1]. %C A061312 Appears in the (n,k)-matching problem A076731. [_Johannes W. Meijer_, Jul 27 2011] %H A061312 G. C. Greubel, <a href="/A061312/b061312.txt">Rows n=0..100 of triangle, flattened</a> %F A061312 T[n,m] = T[n,m-1]-T[n-1,m-1] with T[n,-1] = 0 and T[n,0] = A001563(n) = n*n! %F A061312 T(n,m) = sum(((-1)^j)*binomial(m+1,j)*(n+1-j)!, j=0..m+1) [_Johannes W. Meijer_, Jul 27 2011] %e A061312 0, %e A061312 1, 1, %e A061312 4, 3, 2, %e A061312 18, 14, 11, 9, %e A061312 96, 78, 64, 53, 44, %e A061312 600, 504, 426, 362, 309, 265, %e A061312 4320, 3720, 3216, 2790, 2428, 2119, 1854, %e A061312 35280, 30960, 27240, 24024, 21234, 18806, 16687, 14833, %p A061312 A061312 := proc(n,m): add(((-1)^j)*binomial(m+1,j)*(n+1-j)!, j=0..m+1) end: seq(seq(A061312(n,m), m=0..n), n=0..7); # _Johannes W. Meijer_, Jul 27 2011 %t A061312 T[n_, k_]:= Sum[(-1)^j*Binomial[k + 1, j]*(n + 1 - j)!, {j, 0, k + 1}]; Table[T[n, k], {n, 0, 100}, {k, 0, n}] // Flatten (* _G. C. Greubel_, Aug 13 2018 *) %o A061312 (PARI) for(n=0,20, for(k=0,n, print1(sum(j=0,k+1, (-1)^j*binomial(k+1,j) *(n-j+1)!), ", "))) \\ _G. C. Greubel_, Aug 13 2018 %o A061312 (Magma) [[(&+[(-1)^j*Binomial(k+1,j)*Factorial(n-j+1): j in [0..k+1]]): k in [0..n]]: n in [0..20]]; // _G. C. Greubel_, Aug 13 2018 %Y A061312 Cf. A061018. %Y A061312 From _Johannes W. Meijer_, Jul 27 2011: (Start) %Y A061312 Columns: A001563, A001564, A001565, A001688, A001689, A023044, A023045, A023046, A023047; A000166, A000255, A055790; %Y A061312 The row sums equal A193465. (End) %K A061312 nonn,tabl,easy %O A061312 0,4 %A A061312 _Wouter Meeussen_, Jun 06 2001