cp's OEIS Frontend

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.

A046716 Coefficients of a special case of Poisson-Charlier polynomials.

Original entry on oeis.org

1, 1, 1, 1, 3, 1, 1, 6, 8, 1, 1, 10, 29, 24, 1, 1, 15, 75, 145, 89, 1, 1, 21, 160, 545, 814, 415, 1, 1, 28, 301, 1575, 4179, 5243, 2372, 1, 1, 36, 518, 3836, 15659, 34860, 38618, 16072, 1, 1, 45, 834, 8274, 47775, 163191, 318926, 321690, 125673, 1, 1, 55, 1275, 16290, 125853, 606417, 1809905, 3197210, 2995011, 1112083, 1
Offset: 0

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Keywords

Comments

Diagonals: A000012, A000217; A000012, A002104. - Philippe Deléham, Jun 12 2004
The sequence a(n) = Sum_{k = 0..n} T(n,k)*x^(n-k) is the binomial transform of the sequence b(n) = (n+x-1)! / (x-1)!. - Philippe Deléham, Jun 18 2004

Examples

			Triangle starts:
  1;
  1,  1;
  1,  3,   1;
  1,  6,   8,    1;
  1, 10,  29,   24,     1;
  1, 15,  75,  145,    89,     1;
  1, 21, 160,  545,   814,   415,     1;
  1, 28, 301, 1575,  4179,  5243,  2372,     1;
  1, 36, 518, 3836, 15659, 34860, 38618, 16072,   1;
		

Crossrefs

Diagonals include: A000012, A000217, A002104.
Sums include: A000522 (row), A001339, A023443 (alternating sign row), A082030, A081367.

Programs

  • Magma
    A046716:= func< n,k | (&+[(-1)^j*Binomial(n,k-j)*StirlingFirst(j+n-k, n-k): j in [0..k]]) >;
    [A046716(n,k): k in [0..n], n in [0..12]]; // G. C. Greubel, Jul 31 2024
    
  • Maple
    a := proc(n,k) option remember;
       if k = 0 then 1
    elif k < 0 then 0
    elif k = n then (-1)^n
    else a(n-1,k) - n*a(n-1,k-1) - (n-1)*a(n-2,k-2) fi end:
    A046716 := (n,k) -> abs(a(n,k));
    seq(seq(A046716(n,k),k=0..n),n=0..9); # Peter Luschny, Apr 05 2011
  • Mathematica
    t[, 0] = 1; t[n, k_] := (-1)^k*Sum[(-1)^i*Binomial[n, i]*StirlingS1[i, n-k], {i, n-k, n}]; Table[t[n, k] // Abs, {n, 0, 10}, {k, 0, n}] // Flatten (* Jean-François Alcover, Jan 10 2014 *)
    T[n_, k_]:= T[n,k]= If[k<0 || k>n, 0, If[k==0 || k==n, 1, T[n-1,k] +n*T[n-1,k-1] - (n-1)*T[n-2,k-2]]];
    Table[T[n,k], {n,0,12}, {k,0,n}]//Flatten (* G. C. Greubel, Jul 31 2024 *)
  • SageMath
    def A046716(n, k): return sum(binomial(n, k-j)*stirling_number1(j+n-k, n-k) for j in range(k+1))
    flatten([[A046716(n, k) for k in range(n+1)] for n in range(13)]) # G. C. Greubel, Jul 31 2024

Formula

Enneking and Ahuja reference gives the recurrence t(n, k) = t(n-1, k) - n*t(n-1, k-1) - (n-1)*t(n-2, k-2), with t(n, 0) = 1 and t(n, n) = (-1)^n. This sequence is T(n, k) = (-1)^k * t(n, k).
Sum_{k = 0..n} T(n, k)*x^(n-k) = A000522(n), A001339(n), A082030(n) for x = 1, 2, 3 respectively.
Sum_{k = 0..n} T(n, k)*2^k = A081367(n). - Philippe Deléham, Jun 12 2004
Let P(x, n) = Sum_{k = 0..n} T(n, k)*x^k, then Sum_{n>=0} P(x, n)*t^n / n! = exp(xt)/(1-xt)^(1/x). - Philippe Deléham, Jun 12 2004
T(n, 0) = 1, T(n, k) = (-1)^k * Sum_{i=n-k..n} (-1)^i*C(n, i)*S1(i, n-k), where S1 = Stirling numbers of first kind (A008275).
From G. C. Greubel, Jul 31 2024: (Start)
T(n, k) = T(n-1, k) + n*T(n-1, k-1) - (n-1)*T(n-2, k-2), with T(n, 0) = T(n, n) = 1.
Sum_{k=0..n} (-1)^k*T(n, k) = (-1)^(n+1)*A023443(n). (End)

Extensions

More terms from Vladeta Jovovic, Jun 15 2004