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 1-8 of 8 results.

A111811 Column 0 of the matrix logarithm (A111810) of triangle A098539, which shifts columns left and up under matrix square; these terms are the result of multiplying the element in row n by n!.

Original entry on oeis.org

0, 1, 2, 10, 88, 1096, 11856, -402480, -1891968, 36024603264, 359905478400, -53686393014816000, -644141701131494400, 1790653231402788752593920, 25068910772059830672353280, -1280832036591718248285105113241600
Offset: 0

Views

Author

Paul D. Hanna, Aug 22 2005

Keywords

Comments

Let q=2; the g.f. of column k of A098539^m (matrix power m) is: 1 + Sum_{n>=1} (m*q^k)^n/n! * Product_{j=0..n-1} A(q^j*x).

Examples

			A(x) = x + 2/2!*x^2 + 10/3!*x^3 + 88/4!*x^4 + 1096/5!*x^5 +...
where e.g.f. A(x) satisfies:
x = A(x) - A(x)*A(2*x)/2! + A(x)*A(2*x)*A(2^2*x)/3! - A(x)*A(2*x)*A(2^2*x)*A(2^3*x)/4! + ...
also:
x/(1+x) = A(x) - 2*A(x)*A(2*x)/2! + 2^2*A(x)*A(2*x)*A(2^2*x)/3! - 2^3*A(x)*A(2*x)*A(2^2*x)*A(2^3*x)/4! +...
Let G(x) be the g.f. of A002449 (column 1 of A098539), then
(G(x)-1)/x = 1 + 2*x + 6*x^2 + 26*x^3 + 166*x^4 + 1626*x^5 +...
= 1 + 2*A(x) + 2^2*A(x)*A(2*x)/2! + 2^3*A(x)*A(2*x)*A(2^2*x)/3! + 2^4*A(x)*A(2*x)*A(2^2*x)*A(2^3*x)/4! +...
		

Crossrefs

Cf. A111810 (matrix log), A098539 (triangle), A002449, A111814 (variant), A111941 (q=-1), A111843 (q=3), A111848 (q=4).

Programs

  • PARI
    {a(n,q=2)=local(A=x+x*O(x^n));for(i=1,n, A=x/(1+sum(j=1,n,prod(k=1,j,-subst(A,x,q^k*x))/(j+1)!))); return(n!*polcoeff(A,n))}

Formula

E.g.f. satisfies: x = -Sum_{n>=1} Prod_{j=0..n-1} -A(2^j*x)/(j+1), also: x/(1+x) = Sum_{n>=1} (-2)^(n-1)*Prod_{j=0..n-1} A(2^j*x)/(j+1).

A111810 Matrix log of triangle A098539, which shifts columns left and up under matrix square; these terms are the result of multiplying each element in row n and column k by (n-k)!.

Original entry on oeis.org

0, 1, 0, 2, 2, 0, 10, 4, 4, 0, 88, 20, 8, 8, 0, 1096, 176, 40, 16, 16, 0, 11856, 2192, 352, 80, 32, 32, 0, -402480, 23712, 4384, 704, 160, 64, 64, 0, -1891968, -804960, 47424, 8768, 1408, 320, 128, 128, 0, 36024603264, -3783936, -1609920, 94848, 17536, 2816, 640, 256, 256, 0
Offset: 0

Views

Author

Paul D. Hanna, Aug 22 2005

Keywords

Comments

Column k equals 2^k times column 0 (A111811) when ignoring zeros above the diagonal.

Examples

			Matrix log of A098539, with factorial denominators, begins:
0;
1/1!, 0;
2/2!, 2/1!, 0;
10/3!, 4/2!, 4/1!, 0;
88/4!, 20/3!, 8/2!, 8/1!, 0;
1096/5!, 176/4!, 40/3!, 16/2!, 16/1!, 0;
11856/6!, 2192/5!, 352/4!, 80/3!, 32/2!, 32/1!, 0; ...
		

Crossrefs

Cf. A098539 (triangle), A111811 (column 0), A111813 (variant), A111941 (q=-1), A111843 (q=3), A111848 (q=4).

Programs

  • PARI
    T(n,k,q=2)=local(A=Mat(1),B);if(n
    				

Formula

T(n, k) = 2^k*T(n-k, 0) = 2^k*A111811(n-k) for n>=k>=0.

A098540 Row sums of triangle A098539, which shifts left one column under the matrix square.

Original entry on oeis.org

1, 2, 5, 17, 81, 561, 5905, 98673, 2715025, 126550129, 10211715985, 1450856148081, 367849450783633, 168250359224212593, 140078954639877776273, 213886080203739816320113, 602782564524824650717471633
Offset: 0

Views

Author

Paul D. Hanna, Sep 13 2004

Keywords

Crossrefs

Programs

  • PARI
    a(n)=local(A,B,C,m);A=matrix(1,1);A[1,1]=1; for(m=2,n+1,B=A^2;C=matrix(m,m);for(j=1,m, for(k=1,j, if(j<3 || k==j || k>m-1,C[j,k]=1,if(k==1,C[j,k]=B[j-1,1],C[j,k]=B[j-1,k-1])); ));A=C);sum(i=1,n+1,A[n+1,i])

A098541 Column 2 of triangle A098539, which shifts left one column under the matrix square.

Original entry on oeis.org

1, 4, 20, 140, 1460, 23884, 639156, 28895052, 2260707508, 311748794188, 76846781851828, 34240231941576524, 27825184844063467700, 41547951604100714698572, 114705005843089453002549428
Offset: 0

Views

Author

Paul D. Hanna, Sep 13 2004

Keywords

Crossrefs

Programs

  • PARI
    a(n)=local(A,B,C,m);A=matrix(1,1);A[1,1]=1; for(m=2,n+3,B=A^2;C=matrix(m,m);for(j=1,m, for(k=1,j, if(j<3 || k==j || k>m-1,C[j,k]=1,if(k==1,C[j,k]=B[j-1,1],C[j,k]=B[j-1,k-1])); ));A=C);A[n+3,3]

A111812 Column 3 of triangle A098539, which shifts columns left and up under matrix square.

Original entry on oeis.org

1, 8, 72, 888, 16392, 479736, 23196168, 1909718520, 273790460424, 69532461669880, 31699923943776776, 26220200137673186808, 39689067731528646091272, 110732781183212424923225592
Offset: 0

Views

Author

Paul D. Hanna, Aug 22 2005

Keywords

Examples

			A(x) = 1 + 8*x + 72*x^2 + 888*x^3 + 16392*x^4 + 479736*x^5 +...
		

Crossrefs

Programs

  • PARI
    {a(n,q=2)=local(A=Mat(1),B);if(n<0,0, for(m=1,n+4,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+4,4]))}

Formula

G.f.: A(x) = 1 + Sum_{n>=1} 8^n/n!*Product_{j=0..n-1} L(2^j*x) where L(x) = e.g.f. of A111811 (column 0 of matrix log of A098539) satisfies: x = L(x) - L(x)*L(2*x)/2! + L(x)*L(2*x)*L(2^2*x)/3! - L(x)*L(2*x)*L(2^2*x)*L(2^3*x)/4! + ...

A002449 Number of different types of binary trees of height n.

Original entry on oeis.org

1, 1, 2, 6, 26, 166, 1626, 25510, 664666, 29559718, 2290267226, 314039061414, 77160820913242, 34317392762489766, 27859502236825957466, 41575811106337540656038, 114746581654195790543205466, 588765612737696531880325270438, 5642056933026209681424588087899226
Offset: 0

Views

Author

Keywords

Comments

Two trees have the same type if they have the same number of nodes at each level. - Chams Lahlou, Jan 26 2019
Equals the number of partitions of 2^n-1 into powers of 2 (cf. A018819). a(n) = A018819(2^n-1) = binary partitions of 2^n-1. - Paul D. Hanna, Sep 22 2004

Examples

			G.f. = 1 + x + 2*x^2 + 6*x^3 + 26*x^4 + 166*x^5 + 1626*x^6 + 25510*x^7 + ...
		

References

  • George E. Andrews, Peter Paule, Axel Riese and Volker Strehl, "MacMahon's Partition Analysis V: Bijections, recursions and magic squares," in Algebraic Combinatorics and Applications, edited by Anton Betten, Axel Kohnert, Reinhard Laue and Alfred Wassermann [Proceedings of ALCOMA, September 1999] (Springer, 2001), 1-39.
  • A. Cayley, "On a problem in the partition of numbers," Philosophical Magazine (4) 13 (1857), 245-248; reprinted in his Collected Math. Papers, Vol. 3, pp. 247-249. - Don Knuth, Aug 17 2001
  • R. F. Churchhouse, Congruence properties of the binary partition function. Proc. Cambridge Philos. Soc. 66 1969 371-376.
  • R. F. Churchhouse, Binary partitions, pp. 397-400 of A. O. L. Atkin and B. J. Birch, editors, Computers in Number Theory. Academic Press, NY, 1971.
  • D. E. Knuth, Selected Papers on Analysis of Algorithms, p. 75 (gives asymptotic formula and lower bound).
  • H. Minc, The free commutative entropic logarithmetic. Proc. Roy. Soc. Edinburgh Sect. A 65 1959 177-192 (1959).
  • T. K. Moon (tmoon(AT)artemis.ece.usu.edu), Enumerations of binary trees, types of trees and the number of reversible variable length codes, submitted to Discrete Applied Mathematics, 2000.
  • N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Programs

  • Maple
    d := proc(n) option remember; if n<1 then 1 else sum(d(n-1),k=1..2*k) fi end; A002449 := n -> eval(d(n-1),k=1); # Michael Kleber, Dec 05 2000
  • Mathematica
    lim = 16; p[0] = p[1] = 1; Do[If[OddQ[n], p[n] = p[n - 1], p[n] = p[n - 1] + p[n/2]], {n, 1, 2^lim - 1}]; a[n_] := p[2^n - 1]; Table[a[n], {n, 0, lim}] (* Jean-François Alcover, Sep 20 2011, after Paul D. Hanna *)
  • PARI
    a(n)=local(A,B,C,m);A=matrix(1,1);A[1,1]=1; for(m=2,n+1,B=A^2;C=matrix(m,m);for(j=1,m, for(k=1,j, if(j<3 || k==j || k>m-1,C[j,k]=1,if(k==1,C[j,k]=B[j-1,1],C[j,k]=B[j-1,k-1])); ));A=C);A[n+1,1] \\ Paul D. Hanna
    
  • PARI
    a(n)=polcoeff(1/prod(k=0,n,1-x^(2^k)+O(x^(2^n))),2^n-1)
    
  • PARI
    {a(n, k=2) = if(n<2, n>=0, sum(i=1, k, a(n-1, 2*i)))}; /* Michael Somos, Nov 24 2016 */

Formula

a(n) = A098539(n, 1). - Paul D. Hanna, Sep 13 2004
G.f. A(x) = F(x,1) where F(x,n) satisfies: F(x,n) = F(x,n-1) + xF(x,2n) for n>0 with F(x,0)=1. - Paul D. Hanna, Apr 16 2007
From Benedict W. J. Irwin, Nov 16 2016: (Start)
Conjecture: a(n+2) = Sum_{i_1=1..2}Sum_{i_2=1..2*i_1}...Sum_{i_n=1..2*i_(n-1)} (2*i_n). For example:
a(3) = Sum_{i=1..2} 2*i.
a(4) = Sum_{i=1..2}Sum_{j=1..2*i} 2*j.
a(5) = Sum_{i=1..2}Sum_{j=1..2*i}Sum_{k=1..2*j} 2*k. (End)
The conjecture is true: see Links. - Chams Lahlou, Jan 26 2019

Extensions

Recurrence and more terms from Michael Kleber, Dec 05 2000

A111975 Triangle P, read by rows, that satisfies [P^2](n,k) = P(n+1,k+1) for n>=k>=0, also [P^(2*m)](n,k) = [P^m](n+1,k+1) for all m, where [P^m](n,k) denotes the element at row n, column k, of the matrix power m of P, with P(k,k)=1 and P(k+2,2)=P(k+2,0) for k>=0.

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 4, 4, 4, 1, 16, 16, 16, 8, 1, 96, 96, 96, 64, 16, 1, 896, 896, 896, 704, 256, 32, 1, 13568, 13568, 13568, 11776, 5504, 1024, 64, 1, 345088, 345088, 345088, 317952, 178176, 43776, 4096, 128, 1, 15112192, 15112192, 15112192, 14422016
Offset: 0

Views

Author

Paul D. Hanna, Aug 24 2005

Keywords

Comments

Terms of column 0, column 1 and column 2 in row n are equal for n>2.

Examples

			Triangle P begins:
1;
1,1;
1,2,1;
4,4,4,1;
16,16,16,8,1;
96,96,96,64,16,1;
896,896,896,704,256,32,1;
13568,13568,13568,11776,5504,1024,64,1;
345088,345088,345088,317952,178176,43776,4096,128,1; ...
where P^2 shifts columns left and up one place:
1;
2,1;
4,4,1;
16,16,8,1;
96,96,64,16,1; ...
The matrix inverse, P^-1, equals signed P:
1;
-1,1;
1,-2,1;
-4,4,-4,1;
16,-16,16,-8,1; ...
		

Crossrefs

Cf. A111976 (column 0), A111977 (row sums), A111978 (matrix log), A098539 (variant), A078536 (variant).

Programs

  • PARI
    P(n,k,q=2)=local(A=Mat(1),B);if(n2,(A^q)[i-1,2],1), B[i,j]=(A^q)[i-1,j-1]));));A=B);return(A[n+1,k+1]))

Formula

The g.f. of column k of P^m (ignoring leading zeros) equals: 1 + Sum_{n>=1} (m*2^k)^n/n! * Product_{j=0..n-1} L(2^j*x) where L(x) is the g.f. of column 0 of the matrix log of P (A111979) and satisfies: x-x^2 = Sum_{j>=1}(1-2^j*x)*Prod_{i=0..j-1}L(2^i*x).

A098542 Triangle T, read by rows, such that the matrix square shifts T left one column and up one row, with T(0,0)=T(1,0)=1 and T(n,0)=0 for n>1 and T(n,n)=1 for n>=0.

Original entry on oeis.org

1, 1, 1, 0, 2, 1, 0, 2, 4, 1, 0, 2, 12, 8, 1, 0, 2, 44, 56, 16, 1, 0, 2, 236, 504, 240, 32, 1, 0, 2, 2028, 6776, 4720, 992, 64, 1, 0, 2, 29164, 146552, 139120, 40672, 4032, 128, 1, 0, 2, 719340, 5314680, 6583152, 2500832, 337344, 16256, 256, 1, 0, 2, 30943724
Offset: 0

Views

Author

Paul D. Hanna, Sep 16 2004

Keywords

Comments

Column 2 forms A098543. Row sums form A098544. The absolute value of the matrix inverse equals A098539.

Examples

			Rows of T begin:
[1],
[1,1],
[0,2,1],
[0,2,4,1],
[0,2,12,8,1],
[0,2,44,56,16,1],
[0,2,236,504,240,32,1],
[0,2,2028,6776,4720,992,64,1],
[0,2,29164,146552,139120,40672,4032,128,1],
[0,2,719340,5314680,6583152,2500832,337344,16256,256,1],...
Rows of T^2 begin:
[1],
[2,1],
[2,4,1],
[2,12,8,1],
[2,44,56,16,1],
[2,236,504,240,32,1],...
showing that T shifts left and up under matrix square.
The matrix inverse of T begins:
[1],
[ -1,1],
[2,-2,1],
[ -6,6,-4,1],
[26,-26,20,-8,1],
[ -166,166,-140,72,-16,1],...
the absolute value of which equals triangle A098539.
		

Crossrefs

Cf. A098543, A098544, A098539 (absolute inverse).

Programs

  • PARI
    T(n,k)=local(A,B);A=matrix(1,1);A[1,1]=1;for(m=2,n+1,B=matrix(m,m); for(i=1,m, for(j=1,i,if(i<3 || j==i || j>m-1,B[i,j]=1,if(j==1, B[i,j]=(A^0)[i-1,1],B[i,j]=(A^2)[i-1,j-1]));));A=B);A[n+1,k+1]

Formula

T(n+1, 1) = 2 for n>0; T(n+1, n) = 2^n, T(n+2, n) = 4^n - 2^n for n>=0. Matrix square: [T^2](n, k) = T(n+1, k+1). Matrix inverse: [T^-1](n, k) = (-1)^(n-k)*A098539(n, k). Matrix square inverse: [T^-2](n, k) = (-1)^(n-k)*A098539(n+1, k+1).
Showing 1-8 of 8 results.