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.

Showing 1-6 of 6 results.

A223901 Poly-Cauchy numbers of the second kind hat c_n^(-3).

Original entry on oeis.org

1, -8, 35, -161, 854, -5248, 36966, -294714, 2628600, -25963392, 281529192, -3326287848, 42546905712, -585889457328, 8643254959008, -136013600978784, 2274436197944064, -40278639752011008, 753115809287568384, -14826614346669090816, 306574242780102220800
Offset: 0

Views

Author

Takao Komatsu, Mar 29 2013

Keywords

Comments

The poly-Cauchy numbers of the second kind hat c_n^k can be expressed in terms of the (unsigned) Stirling numbers of the first kind: hat c_n^(k) = (-1)^n*sum(abs(stirling1(n,m))/(m+1)^k, m=0..n).

Crossrefs

Programs

  • Magma
    [&+[StirlingFirst(n, k)*(-1)^k*(k+1)^3: k in [0..n]]: n in [0..25]];
    
  • Mathematica
    Table[Sum[StirlingS1[n, k] (-1)^k (k + 1)^3, {k, 0, n}], {n, 0, 25}]
  • PARI
    a(n) = sum(k=0, n, stirling(n, k, 1)*(-1)^k*(k+1)^3); \\ Michel Marcus, Nov 14 2015

Formula

a(n) = Sum_{k=0..n} Stirling1(n,k) * (-1)^k * (k+1)^3.
E.g.f.: (1 - 7 * log(1 + x) + 6 * log(1 + x)^2 - log(1 + x)^3) / (1 + x). - Ilya Gutkovskiy, Aug 10 2021
From Seiichi Manyama, Apr 15 2025: (Start)
E.g.f.: Sum_{k>=0} (k+1)^3 * (-log(1+x))^k / k!.
a(n) = (-1)^n * Sum_{k=0..3} k! * Stirling2(4,k+1) * |Stirling1(n+1,k+1)|. (End)

A223902 Poly-Cauchy numbers of the second kind hat c_n^(-4).

Original entry on oeis.org

1, -16, 97, -531, 3148, -20940, 156680, -1310840, 12166096, -124281120, 1387313520, -16813355280, 219967479744, -3090914335104, 46439677053120, -743069262651840, 12616998421804416, -226608929801923968, 4292762009479969536, -85545808260446050560, 1789078468694176410624
Offset: 0

Views

Author

Takao Komatsu, Mar 29 2013

Keywords

Comments

The poly-Cauchy numbers of the second kind hat c_n^k can be expressed in terms of the (unsigned) Stirling numbers of the first kind: hat c_n^(k) = (-1)^n*sum(abs(stirling1(n,m))/(m+1)^k, m=0..n).

Crossrefs

Programs

  • Mathematica
    Table[Sum[StirlingS1[n, k] (-1)^k (k + 1)^4, {k, 0, n}], {n, 0, 30}]
  • PARI
    a(n) = sum(k=0, n, stirling(n, k, 1)*(-1)^k*(k+1)^4); \\ Michel Marcus, Nov 14 2015

Formula

a(n) = Sum_{k=0..n} (-1)^k * (k+1)^4 * Stirling1(n,k).
From Seiichi Manyama, Apr 15 2025: (Start)
E.g.f.: Sum_{k>=0} (k+1)^4 * (-log(1+x))^k / k!.
E.g.f.: (1/(1+x)) * Sum_{k=0..4} Stirling2(5,k+1) * (-log(1+x))^k.
a(n) = (-1)^n * Sum_{k=0..4} k! * Stirling2(5,k+1) * |Stirling1(n+1,k+1)|. (End)

A223904 Poly-Cauchy numbers of the second kind hat c_n^(-5).

Original entry on oeis.org

1, -32, 275, -1817, 12134, -87784, 699894, -6158058, 59566464, -630057696, 7246806720, -90151868160, 1207028135520, -17314992935040, 265048030579680, -4313510679824160, 74387763047472000, -1355291635314213120, 26016022725597866880, -524865277479851360640, 11103724030717930095360
Offset: 0

Views

Author

Takao Komatsu, Mar 29 2013

Keywords

Comments

The poly-Cauchy numbers of the second kind hat c_n^k can be expressed in terms of the (unsigned) Stirling numbers of the first kind: hat c_n^(k) = (-1)^n*sum(abs(stirling1(n,m))/(m+1)^k, m=0..n).

Crossrefs

Programs

  • Magma
    [&+[StirlingFirst(n, k)*(-1)^k*(k+1)^5: k in [0..n]]: n in [0..23]]; // Vincenzo Librandi, Aug 03 2013
    
  • Mathematica
    Table[Sum[StirlingS1[n, k] (-1)^k (k + 1)^5, {k, 0, n}], {n, 0, 30}]
  • PARI
    a(n) = sum(k=0, n, (-1)^k*stirling(n, k, 1)*(k+1)^5); \\ Michel Marcus, Nov 14 2015

Formula

a(n) = Sum_{k=0..n} (-1)^k * (k+1)^5 * Stirling1(n,k).
From Seiichi Manyama, Apr 15 2025: (Start)
E.g.f.: Sum_{k>=0} (k+1)^5 * (-log(1+x))^k / k!.
E.g.f.: (1/(1+x)) * Sum_{k=0..5} Stirling2(6,k+1) * (-log(1+x))^k.
a(n) = (-1)^n * Sum_{k=0..5} k! * Stirling2(6,k+1) * |Stirling1(n+1,k+1)|. (End)

A219247 Denominators of poly-Cauchy numbers of the second kind hat c_n^(2).

Original entry on oeis.org

1, 4, 36, 48, 1800, 240, 35280, 20160, 226800, 50400, 3659040, 665280, 1967565600, 2242240, 129729600, 34594560, 2677989600, 66830400, 1857684628800, 39109150080, 3226504881600, 307286179200, 2333316585600, 1285014931200, 2192556726360000, 25057791158400
Offset: 0

Views

Author

Takao Komatsu, Mar 31 2013

Keywords

Comments

The poly-Cauchy numbers of the second kind hat c_n^(k) can be expressed in terms of the (unsigned) Stirling numbers of the first kind: hat c_n^(k) = (-1)^n*sum(abs(stirling1(n,m))/(m+1)^k, m=0..n).

Crossrefs

Cf. A002790, A223899, A224102 (numerators).

Programs

  • Mathematica
    Table[Denominator[Sum[StirlingS1[n, k] (-1)^k/ (k + 1)^2, {k, 0, n}]], {n, 0, 25}]
  • PARI
    a(n) = denominator(sum(k=0, n, stirling(n, k, 1)*(-1)^k/(k+1)^2)); \\ Michel Marcus, Nov 14 2015

A224102 Numerators of poly-Cauchy numbers of the second kind hat c_n^(2).

Original entry on oeis.org

1, -1, 13, -43, 5647, -3401, 2763977, -10326059, 876576493, -1665984623, 1156096889861, -2220482068331, 75970695882225719, -1088498788093641, 855021689397409453, -3324381371618385007, 4010325276269988793421
Offset: 0

Views

Author

Takao Komatsu, Mar 31 2013

Keywords

Comments

The poly-Cauchy numbers of the second kind hat c_n^(k) can be expressed in terms of the (unsigned) Stirling numbers of the first kind: hat c_n^(k) = (-1)^n*sum(abs(stirling1(n,m))/(m+1)^k, m=0..n).

Crossrefs

Cf. A002657, A223899, A219247 (denominators).

Programs

  • Mathematica
    Table[Numerator[Sum[StirlingS1[n, k] (-1)^k/ (k + 1)^2, {k, 0, n}]], {n, 0,
      25}]
  • PARI
    a(n) = numerator(sum(k=0, n, stirling(n, k, 1)*(-1)^k/(k+1)^2)); \\ Michel Marcus, Nov 14 2015

A344639 Array read by ascending antidiagonals: A(n, k) is the number of (n, k)-poly-Cauchy permutations.

Original entry on oeis.org

1, 1, 1, 2, 2, 1, 6, 5, 4, 1, 24, 17, 13, 8, 1, 120, 74, 51, 35, 16, 1, 720, 394, 244, 161, 97, 32, 1, 5040, 2484, 1392, 854, 531, 275, 64, 1, 40320, 18108, 9260, 5248, 3148, 1817, 793, 128, 1, 362880, 149904, 70508, 36966, 20940, 12134, 6411, 2315, 256, 1
Offset: 0

Views

Author

Stefano Spezia, May 25 2021

Keywords

Comments

An (n, k)-poly-Cauchy permutation is a permutation which satisfies the properties listed by Bényi and Ramírez in Definition 1.

Examples

			n\k|   0     1     2     3     4 ...
---+----------------------------
0  |   1     1     1     1     1 ...
1  |   1     2     4     8    16 ...
2  |   2     5    13    35    97 ...
3  |   6    17    51   161   531 ...
4  |  24    74   244   854  3148 ...
...
		

Crossrefs

Rows n=0..2 give A000012, A000079, A007689.
Columns k=0..5 give A000142, A000774, |A223899|, |A223901|, |A223902|, |A223904|.
Main diagonal gives A192563.
Antidiagonal sums give A344640.

Programs

  • Mathematica
    A[n_,k_]:=Sum[Abs[StirlingS1[n,m]](m+1)^k,{m,0,n}]; Flatten[Table[A[n-k,k],{n,0,9},{k,0,n}]]

Formula

A(n, k) = Sum_{m=0..n} abs(S1(n, m)) * (m + 1)^k, where S1 indicates the signed Stirling numbers of first kind (see Theorem 5 in Bényi and Ramírez).
A(n, 0) = n! = A000142(n) (see Example 6 in Bényi and Ramírez).
A(1, k) = 2^k = A000079(k) (see Example 7 in Bényi and Ramírez).
A(2, k) = 2^k + 3^k = A007689(k) (see Example 8 in Bényi and Ramírez).
Sum_{m=0..n} (-1)^m*S2(n, m)*A(m, k) = (-1)^n*(n + 1)^k, where S2 indicates the Stirling numbers of the second kind (see Theorem 9 in Bényi and Ramírez).
A(n, k) = Sum_{j=0..k} j! * abs(S1(n+1, j+1)) * S2(k+1, j+1) (see Theorem 14 in Bényi and Ramírez).
A(n, k) = (n - 1)*A(n-1, k) + Sum_{i=0..k} C(k, i)*A(n-1, k-i) for n > 0 (see Theorem 15 in Bényi and Ramírez).
A(n, k) = Sum_{i=0..n} Sum_{j=0..k} C(n-1, i)*i!*C(k, j)*A(n-1-i, k-j) for n > 0 (see Theorem 17 in Bényi and Ramírez).
A(n, k) = Sum_{m=0..n} Sum_{i=0..m} C(k-i, m-i)*S2(k, i)*abs(S1(n+1, m+1)) (see Theorem 18 in Bényi and Ramírez).
From Seiichi Manyama, Apr 15 2025: (Start)
E.g.f. of column k: Sum_{j>=0} (j+1)^k * (-log(1-x))^j / j!.
E.g.f. of column k: (1/(1-x)) * Sum_{j=0..k} Stirling2(k+1,j+1) * (-log(1-x))^j. (End)
Showing 1-6 of 6 results.