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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A127054 Rectangular table, read by antidiagonals, defined by the following rule: start with all 1's in row zero; from then on, row n+1 equals the partial sums of row n excluding terms in columns k = m*(m+1)/2 (m>=1).

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 1, 4, 3, 1, 1, 10, 9, 4, 1, 1, 34, 33, 15, 5, 1, 1, 154, 153, 65, 23, 6, 1, 1, 874, 873, 339, 119, 32, 7, 1, 1, 5914, 5913, 2103, 719, 186, 42, 8, 1, 1, 46234, 46233, 15171, 5039, 1230, 267, 54, 9, 1, 1, 409114, 409113, 124755, 40319, 9258, 1891, 380
Offset: 0

Views

Author

Paul D. Hanna, Jan 04 2007

Keywords

Comments

Variant of table A125781. Generated by a method similar to Moessner's factorial triangle (A125714).

Examples

			Rows are partial sums excluding terms in columns k = {1,3,6,10,...}:
row 2 = partial sums of [1, 3, 5,6, 8,9,10, 12,13,14,15, ...];
row 3 = partial sums of [1, 9, 23,32, 54,67,81, 113,131,150,170, ...];
row 4 = partial sums of [1, 33, 119,186, 380,511,661, 1045,1283,...].
The terms that are excluded in the partial sums are shown enclosed in
parenthesis in the table below. Rows of this table begin:
1,(1), 1, (1), 1, 1, (1), 1, 1, 1, (1), 1, 1, 1, 1, (1), 1, ...;
1,(2), 3, (4), 5, 6, (7), 8, 9, 10, (11), 12, 13, 14, 15, (16), ...;
1,(4), 9, (15), 23, 32, (42), 54, 67, 81, (96), 113, 131, 150, ...;
1,(10), 33, (65), 119, 186, (267), 380, 511, 661, (831), 1045, ...;
1,(34), 153, (339), 719, 1230, (1891), 2936, 4219, 5765, (7600), ...;
1,(154), 873, (2103), 5039, 9258, (15023), 25148, 38203, 54625, ..;
1,(874), 5913, (15171), 40319, 78522, (133147), 238124, 379339, ...;
1,(5914), 46233, (124755), 362879, 742218, (1305847), 2477468, ...;
1,(46234), 409113, (1151331), 3628799, 7742058, (14059423), ...;
1,(409114), 4037913, (11779971), 39916799, 88369098, (164977399),...;
Columns include:
k=1: A003422 (Left factorials: !n = Sum k!, k=0..n-1);
k=2: A007489 (Sum of k!, k=1..n);
k=3: A097422 (Sum{k=1 to n} H(k) k!, where H(k) = sum{j=1 to k} 1/j);
k=4: A033312 (n! - 1);
k=5: Partial sums of A001705;
k=6: partial sums of A000399 (Stirling numbers of first kind s(n,3)).
		

Crossrefs

Cf. variants: A125781, A125714; antidiagonal sums: A127055; diagonal: A127056; columns: A003422, A007489, A097422, A033312.

Programs

  • Maple
    {T(n,k)=local(A=0,b=2,c=0,d=0);if(n==0,A=1, until(d>k,if(c==b*(b-1)/2,b+=1,A+=T(n-1,c);d+=1);c+=1));A}

A326326 T(n, k) = [x^k] Sum_{j=0..n} Pochhammer(x, j), for 0 <= k <= n, triangle read by rows.

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 1, 4, 4, 1, 1, 10, 15, 7, 1, 1, 34, 65, 42, 11, 1, 1, 154, 339, 267, 96, 16, 1, 1, 874, 2103, 1891, 831, 191, 22, 1, 1, 5914, 15171, 15023, 7600, 2151, 344, 29, 1, 1, 46234, 124755, 133147, 74884, 24600, 4880, 575, 37, 1
Offset: 0

Views

Author

Peter Luschny, Jul 02 2019

Keywords

Examples

			Triangle starts:
[0] [1]
[1] [1, 1]
[2] [1, 2,     1]
[3] [1, 4,     4,      1]
[4] [1, 10,    15,     7,      1]
[5] [1, 34,    65,     42,     11,    1]
[6] [1, 154,   339,    267,    96,    16,    1]
[7] [1, 874,   2103,   1891,   831,   191,   22,   1]
[8] [1, 5914,  15171,  15023,  7600,  2151,  344,  29,  1]
[9] [1, 46234, 124755, 133147, 74884, 24600, 4880, 575, 37, 1]
		

Crossrefs

Same construction for the falling factorial is A176663.
The inverse of the lower triangular matrix is the signed form of A256894.
Second column is A003422(n) and row sums are A003422(n+1).
Alternating row sums are A000007.
Third column is A097422.

Programs

  • Maple
    with(PolynomialTools):
    T_row := n -> CoefficientList(expand(add(pochhammer(x, j), j=0..n)),x):
    ListTools:-Flatten([seq(T_row(n), n=0..9)]);
  • Mathematica
    Table[CoefficientList[FunctionExpand[Sum[Pochhammer[x, k], {k, 0, n}]], x], {n, 0, 10}] // Flatten

Formula

Sum_{k=0..n} T(n, k)*x^k = Sum_{k=0..n} (x)^k, where (x)^k denotes the rising factorial.
Conjecture: T(n,k) = Sum_{i=0..n} A132393(i,k) for 0 <= k <= n. - Werner Schulte, Mar 30 2022

A330016 a(n) = Sum_{k=1..n} (-1)^(n - k) * H(k) * k!, where H(k) is the k-th harmonic number.

Original entry on oeis.org

0, 1, 2, 9, 41, 233, 1531, 11537, 98047, 928529, 9700111, 110843729, 1375599151, 18427159889, 265038487471, 4074124514129, 66660157879471, 1156745432699729, 21220242625821871, 410344904191816529, 8342603132569783471, 177902207647600456529, 3970574571687854263471
Offset: 0

Views

Author

Ilya Gutkovskiy, Nov 27 2019

Keywords

Crossrefs

Programs

  • Mathematica
    Table[Sum[(-1)^(n - k) HarmonicNumber[k] k!, {k, 1, n}], {n, 0, 22}]

Formula

a(n) = Sum_{k=1..n} (-1)^(n - k) * |Stirling1(k+1,2)|.
Showing 1-3 of 3 results.