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 1-5 of 5 results.

A125800 Rectangular table where column k equals row sums of matrix power A078122^k, read by antidiagonals.

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 1, 5, 3, 1, 1, 23, 12, 4, 1, 1, 239, 93, 22, 5, 1, 1, 5828, 1632, 238, 35, 6, 1, 1, 342383, 68457, 5827, 485, 51, 7, 1, 1, 50110484, 7112055, 342382, 15200, 861, 70, 8, 1, 1, 18757984046, 1879090014, 50110483, 1144664, 32856, 1393, 92, 9, 1
Offset: 0

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Author

Paul D. Hanna, Dec 10 2006

Keywords

Comments

Determinant of n X n upper left submatrix is 3^(n*(n-1)*(n-2)/6).
This table is related to partitions of numbers into powers of 3 (see A078122).
Triangle A078122 shifts left one column under matrix cube.
Column 1 is A078125, which equals row sums of A078122;
column 2 is A078124, which equals row sums of A078122^2.

Examples

			Recurrence T(n,k) = T(n,k-1) + T(n-1,3*k) is illustrated by:
  T(3,3) = T(3,2) + T(2,9) = 93 + 145 = 238;
  T(4,3) = T(4,2) + T(3,9) = 1632 + 4195 = 5827;
  T(5,3) = T(5,2) + T(4,9) = 68457 + 273925 = 342382.
Rows of this table begin:
  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, ...;
  1, 5, 12, 22, 35, 51, 70, 92, 117, 145, 176, 210, ...;
  1, 23, 93, 238, 485, 861, 1393, 2108, 3033, 4195, 5621, ...;
  1, 239, 1632, 5827, 15200, 32856, 62629, 109082, 177507, 273925,...;
  1, 5828, 68457, 342382, 1144664, 3013980, 6769672, 13570796, ...;
  1, 342383, 7112055, 50110483, 215155493, 690729981, 1828979530, ...;
  1, 50110484, 1879090014, 18757984045, 103674882878, 406279238154,..;
  1, 18757984046, 1287814075131, 18318289003447, 130648799730635, ...;
Triangle A078122 begins:
  1;
  1,     1;
  1,     3,      1;
  1,    12,      9,     1;
  1,    93,    117,    27,    1;
  1,  1632,   3033,  1080,   81,   1;
  1, 68457, 177507, 86373, 9801, 243, 1; ...
where row sums form column 1 of this table A125790,
and column k of A078122 equals column 3^k - 1 of this table A125800.
Matrix square A078122^2 begins:
     1;
     2,     1;
     5,     6,     1;
    23,    51,    18,    1;
   239,   861,   477,   54,   1;
  5828, 32856, 25263, 4347, 162, 1; ...
where row sums form column 2 of this table A125790,
and column 0 of A078122^2 forms column 1 of this table A125790.
		

Crossrefs

Cf. A078122; columns: A078125, A078124, A125801, A125802, A125803; A125804 (diagonal), A125805 (antidiagonal sums); related table: A125800 (q=2).

Programs

  • Maple
    f[0]:= 1/(1-z):
    S[0]:= series(f[0],z,21):
    for n from 1 to 20 do
      ff:= unapply(f[n-1],z);
      f[n]:= simplify(1/3*sum(ff(w*z^(1/3)),w=RootOf(Z^3-1,Z)))/(1-z);
      S[n]:= series(f[n],z,21-n)
    od:
    seq(seq(coeff(S[s-i],z,i),i=0..s),s=0..20); # Robert Israel, Jun 02 2019
  • Mathematica
    T[0, ] = T[, 0] = 1; T[n_, k_] := T[n, k] = T[n, k-1] + T[n-1, 3 k]; Table[T[n-k, k], {n, 0, 9}, {k, 0, n}] // Flatten (* Jean-François Alcover, Jan 08 2016 *)
  • PARI
    T(n,k,p=0,q=3)=local(A=Mat(1), B); if(n

Formula

T(n,k) = T(n,k-1) + T(n-1,3*k) for n > 0, k > 0, with T(0,n)=T(n,0)=1 for n >= 0.
G.f. of row n is g_n(z) where g_{n+1}(z) = (1-z)^(-1)*Sum_{w^3=1} g_n(w*z^(1/3)) (the sum being over the cube roots of unity). - Robert Israel, Jun 02 2019

A125801 Column 3 of table A125800; also equals row sums of matrix power A078122^3.

Original entry on oeis.org

1, 4, 22, 238, 5827, 342382, 50110483, 18757984045, 18318289003447, 47398244089264546, 329030840161393127680, 6190927493941741957366099, 318447442589056401640929570895, 45106654667152833836835578059359838
Offset: 0

Views

Author

Paul D. Hanna, Dec 10 2006

Keywords

Comments

Triangle A078122 shifts left one column under matrix cube and is related to partitions into powers of 3.
Number of partitions of 3^n into powers of 3, excluding the trivial partition 3^n=3^n. - Valentin Bakoev, Feb 20 2009

Examples

			To obtain t_3(5,1) we use the table T, defined as T(i,j) = t_3(i,j), for i=1,2,...,5(=n), and j=0,1,2,...,81(= k*m^{n-1}). It is 1,1,1,1,1,1,...1; 1,4,7,10,13,...,82; 1,22,70,145,247,376,532,715,925,1162; 1,238,1393,4195; 1,5827; Column 1 contains the first 5 terms of A125801. - _Valentin Bakoev_, Feb 20 2009
		

Crossrefs

Cf. A125800, A078122; other columns: A078125, A078124, A125802, A125803.

Programs

  • Maple
    g:= proc(b, n, k) option remember; local t; if b<0 then 0 elif b=0 or n=0 or k<=1 then 1 elif b>=n then add (g(b-t, n, k) *binomial (n+1, t) *(-1)^(t+1), t=1..n+1); else g(b-1, n, k) +g(b*k, n-1, k) fi end: a:= n-> g(1, n+1,3)-1: seq(a(n), n=0..25); # Alois P. Heinz, Feb 27 2009
  • Mathematica
    T[0, ] = T[, 0] = 1; T[n_, k_] := T[n, k] = T[n, k-1] + T[n-1, 3 k];
    a[n_] := T[n, 3]; Table[an = a[n]; Print["a(", n, ") = ", an]; an, {n, 0, 15}] (* Jean-François Alcover, Jan 21 2017 *)
  • PARI
    a(n)=local(p=3,q=3,A=Mat(1), B); for(m=1, n+1, B=matrix(m, m); for(i=1, m, for(j=1, i, if(j==i || j==1, B[i, j]=1, B[i, j]=(A^q)[i-1, j-1]); )); A=B); return(sum(c=0,n,(A^p)[n+1,c+1]))

Formula

Denote the sum: m^n +m^n + ... + m^n, k times, by k*m^n (m > 1, n > 0 and k are positive integers). The general formula for the number of all partitions of the sum k*m^n into powers of m smaller than m^n, is t_m(n, k)= 1 when n=1 or k=0, or = t_m(n, k-1) + Sum_{j=1..m} t_m(n-1, (k-1)*n+j)}, when n > 1 and k > 0. A125801 is obtained for m=3 and n=1,2,3,... - Valentin Bakoev, Feb 20 2009
From Valentin Bakoev, Feb 20 2009: (Start)
Adding 1 to the terms of A125801 we obtain A078125.
For given m, the general formula for t_m(n, k) and the corresponding tables T, computed as in the example, determine a family of related sequences (placed in the rows or in the columns of T). For example, the sequences from the 3rd, 4th, etc. rows of the given table are not represented in the OEIS till now. (End)
a(n) = A145515(n+1,3)-1. - Alois P. Heinz, Feb 27 2009

A125803 Column 5 of table A125800; also equals row sums of matrix power A078122^5.

Original entry on oeis.org

1, 6, 51, 861, 32856, 3013980, 690729981, 406279238154, 625750288074015, 2563196032703643450, 28270494794022487841733, 848050124165724284639262951, 69769378541879435090796205851249
Offset: 0

Views

Author

Paul D. Hanna, Dec 10 2006

Keywords

Comments

Triangle A078122 shifts left one column under matrix cube and is related to partitions into powers of 3.

Crossrefs

Cf. A125800, A078122; other columns: A078125, A078124, A125801, A125802.

Programs

  • PARI
    a(n)=local(p=5,q=3,A=Mat(1), B); for(m=1, n+1, B=matrix(m, m); for(i=1, m, for(j=1, i, if(j==i || j==1, B[i, j]=1, B[i, j]=(A^q)[i-1, j-1]); )); A=B); return(sum(c=0,n,(A^p)[n+1,c+1]))

A125804 Main diagonal of table A125800.

Original entry on oeis.org

1, 2, 12, 238, 15200, 3013980, 1828979530, 3373190565626, 18837339867421686, 317817051628161116674, 16176220447967300610844988, 2481251352301850541661479580329, 1146112129196402690505198891390847384
Offset: 0

Views

Author

Paul D. Hanna, Dec 10 2006

Keywords

Comments

Table A125800 is related to partitions into powers of 3; column k of A125800 equals row sums of matrix power A078122^k, where triangle A078122 shifts left one column under matrix cube.

Crossrefs

Cf. A125800, A078122; columns: A078125, A078124, A125801, A125802, A125803; A125805 (antidiagonal sums).

Programs

  • PARI
    a(n)=local(q=3,A=Mat(1), B); for(m=1, n+1, B=matrix(m, m); for(i=1, m, for(j=1, i, if(j==i || j==1, B[i, j]=1, B[i, j]=(A^q)[i-1, j-1]); )); A=B); return(sum(c=0,n,(A^n)[n+1,c+1]))

A125805 Antidiagonal sums of table A125800.

Original entry on oeis.org

1, 2, 4, 10, 41, 361, 7741, 417212, 57581062, 20688363559, 19625079296963, 49742424992663959, 340292157995636104240, 6337196928437059669994069, 323627960380394115802942263514, 45610724032832026072070666274435391
Offset: 0

Views

Author

Paul D. Hanna, Dec 10 2006

Keywords

Comments

Table A125800 is related to partitions into powers of 3; column k of A125800 equals row sums of matrix power A078122^k, where triangle A078122 shifts left one column under matrix cube.

Crossrefs

Cf. A125800, A078122; columns: A078125, A078124, A125801, A125802, A125803; A125804 (diagonal).

Programs

  • PARI
    a(n)=local(q=3,A=Mat(1), B); for(m=1, n+1, B=matrix(m, m); for(i=1, m, for(j=1, i, if(j==i || j==1, B[i, j]=1, B[i, j]=(A^q)[i-1, j-1]); )); A=B); return(sum(c=0,n,(A^(c+1))[n-c+1,1]))
Showing 1-5 of 5 results.