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.

Previous Showing 11-16 of 16 results.

A125802 Column 4 of table A125800; also equals row sums of matrix power A078122^4.

Original entry on oeis.org

1, 5, 35, 485, 15200, 1144664, 215155493, 103674882878, 130648799730635, 437302448840089232, 3936208033244539574405, 96244898501021613327012635, 6446494058446469307795159512465, 1191218783863555524342034469450207222
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, A125803.

Programs

  • PARI
    a(n)=local(p=4,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]))

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]))

A078123 Square of infinite lower triangular matrix A078122.

Original entry on oeis.org

1, 2, 1, 5, 6, 1, 23, 51, 18, 1, 239, 861, 477, 54, 1, 5828, 32856, 25263, 4347, 162, 1, 342383, 3013980, 3016107, 699813, 39285, 486, 1, 50110484, 690729981, 865184724, 253656252, 19053063, 354051, 1458, 1, 18757984046, 406279238154
Offset: 0

Views

Author

Paul D. Hanna, Nov 18 2002

Keywords

Examples

			Square of A078122 = A078123 as can be seen by 4 X 4 submatrix:
[1,_0,_0,0]^2=[_1,_0,_0,_0]
[1,_1,_0,0]___[_2,_1,_0,_0]
[1,_3,_1,0]___[_5,_6,_1,_0]
[1,12,_9,1]___[23,51,18,_1]
		

Crossrefs

Programs

  • Maple
    S:= proc(i, j) option remember;
           add(M(i, k)*M(k, j), k=0..i)
        end:
    M:= proc(i, j) option remember; `if`(j=0 or i=j, 1,
           add(S(i-1, k)*M(k, j-1), k=0..i-1))
        end:
    seq(seq(S(n,k), k=0..n), n=0..10);  # Alois P. Heinz, Feb 27 2015
  • Mathematica
    S[i_, j_] := S[i, j] = Sum[M[i, k]*M[k, j], {k, 0, i}]; M[i_, j_] := M[i, j] = If[j == 0 || i == j, 1, Sum[S[i-1, k]*M[k, j-1], {k, 0, i-1}]]; Table[Table[S[n, k], {k, 0, n}], {n, 0, 10}] // Flatten (* Jean-François Alcover, Mar 06 2015, after Alois P. Heinz *)

Formula

M(1, j) = A078125(j), M(j+1, j)=2*3^j.

A111841 Number of partitions of 3^n-1 into powers of 3, also equals column 0 of triangle A111840, which shifts columns left and up under matrix cube.

Original entry on oeis.org

1, 1, 3, 18, 216, 5589, 336555, 49768101, 18707873562, 18299531019402, 47379925800261099, 328983441917303863134, 6190598463101580564238419, 318441251661562459898972204796, 45106336219710244780433937129788943
Offset: 0

Views

Author

Paul D. Hanna, Aug 22 2005

Keywords

Comments

Let q=3; a(n) equals the partitions of q^n-1 into powers of q, or, the coefficient of x^(q^n-1) in 1/Product_{j>=0}(1-x^(q^j)).

Crossrefs

Cf. A111840, A078124 (variant).
Cf. A002449.

Programs

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

Formula

a(n) = [x^(3^n-1)] Product_{k>=0} 1/(1-x^(3^k)).

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]))
Previous Showing 11-16 of 16 results.