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.

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A074051 For each n there are uniquely determined numbers a(n) and b(n) and a polynomial p_n(x) such that for all integers m we have Sum_{i=1..m}i^n(i+1)! = a(n)*Sum_{i=1..m} (i+1)! + p_n(m)*(m+2)! + b(n). The sequence b(n) is A074052.

Original entry on oeis.org

1, -1, 0, 3, -7, 0, 59, -217, 146, 2593, -15551, 32802, 160709, -1856621, 7971872, 1299951, -287113779, 2262481448, -7275903849, -36989148757, 698330745002, -4867040141851, 10231044332629, 184216198044034, -2679722886596295, 17971204188130391, -17976259717948832
Offset: 0

Views

Author

Jan Fricke, Aug 14 2002

Keywords

Comments

If a(n)=0 then Sum_{i>=1}i^n(i+1)! = b(n) in the p-adic numbers. The only known numbers n with a(n)=0 are 2 and 5.
a(n)*(-1)^n gives the alternating row sums of the Sheffer triangle A143494 (2-restricted Stirling2). - Wolfdieter Lang, Oct 06 2011

Examples

			a(2)=0 because Sum_{i=1..m}i^2(i+1)! = (m-1)(m+2)!+2.
a(3)=3 because Sum_{i=1..m}i^3(i+1)! = 3*Sum_{i=1..m}(i+1)!+(m^2-m-1)(m+2)!+2.
		

Crossrefs

Programs

  • Maple
    alias(S2 = combinat[stirling2]);
    A074051 := proc(n) local k;
    1 + add((-1)^(n+k) * (S2(n+1, k+1) - S2(n+2, k+1)), k = 0..n) end:
    seq(A074051(i), i = 0..26); # Peter Luschny, Apr 17 2011
  • Mathematica
    A[a_] := Module[{p, k}, p[n_] = 0; For[k = a - 1, k >= 0, k--, p[n_] = Expand[p[n] + n^k Coefficient[n^a - (n + 2)p[n] + p[n - 1], n^(k + 1)]] ]; Expand[n^a - (n + 2)p[n] + p[n - 1]] ]
    (* Second program: *)
    a[n_] := (-1)^n (BellB[n+2, -1] - BellB[n+1, -1]);
    Table[a[n], {n, 0, 30}] (* Jean-François Alcover, Jun 21 2018, after Peter Luschny *)
  • Python
    from itertools import accumulate
    def A074051_list(size):
        if size < 1: return []
        L, accu = [], [1]
        for n in range(size-1):
            accu = list(accumulate([-accu[-1]] + accu))
            L.append(-(-1)**n*accu[-2])
        return L
    print(A074051_list(28)) # Peter Luschny, Apr 25 2016

Formula

From Vladeta Jovovic, Jan 27 2005: (Start)
Second inverse binomial transform of A000587.
E.g.f.: exp(1 - 2*x - exp(-x)).
G.f.: Sum_{k >= 0}((x/(1+2*x))^k/Product_{l=0..k}(1 + l*x/(1+2*x)))/(1+2*x).
a(n) = Sum_{k=0..n} (-1)^(n-k)*(k^2-3*k+1)*Stirling2(n, k). (End)
a(n) = (-1)^n*(A000587(n+2)-A000587(n+1)). - Peter Luschny, Apr 17 2011
From Sergei N. Gladkovskii, Sep 28 2012 to Apr 22 2013: (Start)
Continued fractions:
G.f.: 1/U(0) where U(k)= x*k + 1 + x + x^2*(k+1)/U(k+1).
G.f.: -1/U(0) where U(k)= -x*k - 1 - x + x^2*(k+1)/U(k+1).
G.f.: 1/(U(0) - x) where U(k)= 1 + x + x*(k+1)/(1 - x/U(k+1)).
G.f.: 1/(U(0) + x) where U(k)= 1 + x*(2*k+1) - x*(k+1)/(1 + x/U(k+1)).
G.f.: 1/G(0) where G(k)= 1 + 2*x/(1 + 1/(1 + 2*x*(k+1)/G(k+1))).
G.f.: 1 - 2*x/(G(0) + 2*x) where G(k)= 1 + 1/(1 + 2*x*(k+1)/(1 + 2*x/G(k+1))).
G.f.: (G(0) - 1)/(x-1) where G(k) = 1 - 1/(1+k*x+2*x)/(1-x/(x-1/G(k+1))).
G.f.: (G(0)-2-2*x)/x^2 where G(k) = 1 + 1/(1+k*x)/(1-x/(x+1/G(k+1) )).
G.f.: (S-2-2*x)/x^2 where S = sum(k>=0, (2 + x*k)*x^k/prod(i=0..k, (1+x*i))).
G.f.: (G(0)-2)/x where G(k) = 1 + 1/(1+k*x+x)/(1-x/(x+1/G(k+1))).
G.f.: (1+x)/x/Q(0) - 1/x, where Q(k)= 1 + x - x/(1 + x*(k+1)/Q(k+1)). (End)
a(n) = exp(1) * (-1)^n * Sum_{k>=0} (-1)^k * (k+2)^n / k!. - Ilya Gutkovskiy, Sep 02 2021

Extensions

More terms from Vladeta Jovovic, Jan 27 2005

A197184 Triangle of polynomial coefficients of the polynomial factors defined in A074051.

Original entry on oeis.org

1, -1, 1, -1, -1, 1, 7, -2, -1, 1, -13, 12, -3, -1, 1, -17, -22, 18, -4, -1, 1, 199, -45, -35, 25, -5, -1, 1, -605, 465, -84, -53, 33, -6, -1, 1, -225, -1449, 910, -133, -77, 42, -7, -1, 1, 11703, -864, -3094, 1594, -190, -108, 52, -8, -1, 1, -59317, 33780, -1380, -6027, 2583, -252, -147, 63, -9, -1, 1, 83143, -179398, 78567, -771, -10899, 3948, -315, -195, 75, -10, -1, 1, 991671, 271073, -461978, 159115, 2882, -18546, 5764, -374, -253, 88, -11, -1, 1
Offset: 1

Views

Author

R. J. Mathar, Oct 11 2011

Keywords

Comments

The triangle T(n,k), 0<=kA074052(n) + A074051(n)*sum_{i=1..m} (i+1)! + p_n(m) *(m+2)!.

Examples

			1;   1
-1,1;  -1+x
-1,-1,1;  -1-x+x^2
7,-2,-1,1;  7-2*x-x^2+x^3
-13,12,-3,-1,1;  -13+12*x-3*x^2-x^3+x^4
-17,-22,18,-4,-1,1;   -17-22*x+18*x^2-4*x^3-x^4+x^5
		

Formula

A074052(n) + 2*A074051(n) + 6*p_n(1) = 2. - R. J. Mathar, Oct 13 2011
(x+2)*p_n(x)-p_n(x-1) = x^n-A074051(n). - R. J. Mathar, Oct 13 2011
Conjectures on p_n(x)= sum_{k=0..n-1} T(n,k)*x^k:
T(n,n-1) = 1.
T(n,n-2) = -1.
T(n,n-3) = -(n-2).
T(n,n-4) = A055998(n-2).
T(n,n-5) = -(n-2)*(n^2-4*n+21)/6.
T(n,n-6) = (n-5)*(n-2)*(n^2-19*n-24)/24.
Showing 1-2 of 2 results.