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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A125784 Column 4 of table A125781.

Original entry on oeis.org

1, 5, 21, 91, 433, 2307, 13804, 92433, 688611, 5670713, 51291468, 506502769, 5430460072, 62894124926, 783259655434, 10445143907067, 148592182641759, 2247301621235992, 36021020633412788, 610161098104988668
Offset: 0

Views

Author

Paul D. Hanna, Dec 09 2006

Keywords

Comments

Column k of triangle A091351 = row sums of matrix power A091351^k for k>=0.

Examples

			a(n) = A125783(n) + A125786(n-1) for n>0:
A125783 begins: 1, 4, 14, 52, 217, 1033, 5604, 34416, 237328, ...
and A125786 begins: 1, 7, 39, 216, 1274, 8200, 58017, 451283, ...
term-by-term addition forms this sequence.
This sequence can also be derived from the matrix square A091351^2:
1;
2, [1];
4, [4, 1];
9, [14, 6, 1];
24, [52, 30, 8, 1];
77, [217, 153, 52, 10, 1];
295, [1033, 845, 336, 80, 12, 1];
1329, [5604, 5152, 2294, 625, 114, 14, 1]; ...
The terms enclosed in square barackets sum to equal this sequence.
		

Crossrefs

Cf. A091351; other columns: A091352, A125782, A125783, A125785, A125786.

Formula

a(n) = Sum_{k=0..n} [A091351^2](n+1,k+1) where A091351^2 is the matrix square of A091351.

A125785 Column 5 of table A125781.

Original entry on oeis.org

1, 6, 29, 141, 739, 4276, 27483, 195978, 1544074, 13371684, 126591212, 1303252476, 14517950305, 174196495882, 2241822436160, 30826098464147, 451299846525541, 7012090426122158, 115289977296253757, 2000463474160276658
Offset: 0

Views

Author

Paul D. Hanna, Dec 09 2006

Keywords

Comments

A091352 equals column 1 of both table A125781 and triangle A091351.

Examples

			A091352 begins: [1, 2, 4, 9, 24, 77, 295, 1329, 6934, 41351, ...];
a(5) = A091352(8) - 2*A091352(7) = 6934 - 2*1329 = 4276.
		

Crossrefs

Cf. A125781; other columns: A091352, A125782, A125783, A125784, A125786.

Formula

a(n) = A091352(n+2) - 2*A091352(n+1). a(n) = A125782(n+1) - A125783(n+1).

A125786 Column 6 of table A125781.

Original entry on oeis.org

1, 7, 39, 216, 1274, 8200, 58017, 451283, 3847960, 35818351, 362337006, 3965467281, 46749441514, 591291743032, 7993582141984, 115104783083605, 1759853074058289, 28485332959460764, 486811835886953020
Offset: 0

Views

Author

Paul D. Hanna, Dec 09 2006

Keywords

Comments

Column k of triangle A091351 = row sums of matrix power A091351^k for k>=0.

Examples

			a(n) = A125784(n+1) - A125783(n+1) for n>0:
A125784 begins: 1, 5, 21, 91, 433, 2307, 13804, 92433, 688611, ...;
A125783 begins: 1, 4, 14, 52, 217, 1033, 5604, 34416, 237328, ...;
term-by-term differences form this sequence.
This sequence can also be derived from the matrix square A091351^2:
1;
2, 1;
4, 4, [1];
9, 14, [6, 1];
24, 52, [30, 8, 1];
77, 217, [153, 52, 10, 1];
295, 1033, [845, 336, 80, 12, 1];
1329, 5604, [5152, 2294, 625, 114, 14, 1]; ...
the terms enclosed in square barackets sum to equal this sequence.
		

Crossrefs

Cf. A125781; other columns: A091352, A125782, A125783, A125784, A125785.

Formula

a(n) = Sum_{k=0..n} [A091351^2](n+2,k+2) where A091351^2 is the matrix square of A091351.

A101897 Triangle T, read by rows, such that column k equals column 0 of T^(k+1), where column 0 of T allows the n-th row sums to be zero for n>0 and where T^k is the k-th power of T as a lower triangular matrix.

Original entry on oeis.org

1, -1, 1, 1, -2, 1, -2, 4, -3, 1, 5, -11, 9, -4, 1, -17, 38, -33, 16, -5, 1, 71, -162, 145, -74, 25, -6, 1, -357, 824, -753, 396, -140, 36, -7, 1, 2101, -4892, 4535, -2434, 885, -237, 49, -8, 1, -14203, 33286, -31185, 16982, -6295, 1730, -371, 64, -9, 1, 108609, -255824, 241621, -133012, 50001, -13992, 3073, -548, 81
Offset: 0

Views

Author

Paul D. Hanna, Dec 20 2004

Keywords

Comments

Column 0 forms A101900. Absolute row sums form A101901.

Examples

			Rows begin:
        1;
       -1,     1;
        1,    -2,      1;
       -2,     4,     -3,     1;
        5,   -11,      9,    -4,     1;
      -17,    38,    -33,    16,    -5,    1;
       71,  -162,    145,   -74,    25,   -6,   1;
     -357,   824,   -753,   396,  -140,   36,  -7,   1,
     2101, -4892,   4535, -2434,   885, -237,  49,  -8,  1;
   -14203, 33286, -31185, 16982, -6295, 1730, -371, 64, -9, 1;
      ...
		

Crossrefs

Programs

  • Mathematica
    t[n_, k_] := t[n, k] = If[k>n || n<0 || k<0, 0, If[k==n, 1, If[k==0, -Sum[t[n, j], {j, 1, n}], Sum[t[n-k, j]*t[j+k-1, k-1], {j, 0, n-k}]]]]; Table[t[n ,k], {n,0,10}, {k, 0, n}] //Flatten (* Amiram Eldar, Nov 26 2018 *)
  • PARI
    {T(n,k)=if(k>n||n<0||k<0,0,if(k==n,1, if(k==0,-sum(j=1,n,T(n,j)), sum(j=0,n-k,T(n-k,j)*T(j+k-1,k-1));));)}

Formula

T(n, k) = Sum_{j=0..n-k} T(n-k, j)*T(j+k-1, k-1) for n >= k > 0 with T(0, 0) = 1 and T(n, 0) = -Sum_{j=1, n} T(n, j) for n > 0.

A135902 Triangle T, read by rows, where column k of T = column 0 of T^(k+1) for k>0, with column 0 of T = column 0 of T^3 shift right.

Original entry on oeis.org

1, 1, 1, 3, 2, 1, 15, 8, 3, 1, 102, 47, 15, 4, 1, 860, 356, 102, 24, 5, 1, 8548, 3252, 860, 186, 35, 6, 1, 97094, 34448, 8548, 1736, 305, 48, 7, 1, 1234324, 412546, 97094, 18754, 3130, 465, 63, 8, 1, 17302880, 5488222, 1234324, 228658, 36630, 5212, 672, 80, 9, 1
Offset: 0

Views

Author

Paul D. Hanna, Dec 18 2007

Keywords

Comments

This is a variant of permutation triangle P = A094587, A094587(n,k) = n!/k!, which may be defined by: triangular matrix P where column k of P = column 0 of P^(k+1), with column 0 of P = column 0 of P^2 shift right.

Examples

			Triangle T begins:
1;
1, 1;
3, 2, 1;
15, 8, 3, 1;
102, 47, 15, 4, 1;
860, 356, 102, 24, 5, 1;
8548, 3252, 860, 186, 35, 6, 1;
97094, 34448, 8548, 1736, 305, 48, 7, 1;
1234324, 412546, 97094, 18754, 3130, 465, 63, 8, 1;
17302880, 5488222, 1234324, 228658, 36630, 5212, 672, 80, 9, 1; ...
where column k of T = column 0 of T^(k+1)
with column 0 of T = column 0 of T^3 shift right.
Matrix square of T, T^2, begins:
1;
2, 1;
8, 4, 1;
47, 22, 6, 1;
356, 156, 42, 8, 1;
3252, 1343, 351, 68, 10, 1;
34448, 13493, 3415, 656, 100, 12, 1; ...
where column 0 of T^2 = column 1 of T.
Matrix cube of T, T^3, begins:
1;
3, 1;
15, 6, 1;
102, 42, 9, 1;
860, 351, 81, 12, 1;
8548, 3415, 807, 132, 15, 1;
97094, 37795, 8967, 1530, 195, 18, 1; ...
where column 0 of T^3 = column 2 of T = column 0 of T shift left;
also, column 1 of T^3 = column 2 of T^2.
		

Crossrefs

Cf. columns: A135903, A135904, A135905; variants: A091351, A094587.

Programs

  • PARI
    T(n, k)=if(k>n || n<0 || k<0, 0, if(k==n,1,if(k==0, T(n+1,2), sum(j=0, n-k, T(n-k, j)*T(j+k-1, k-1))); ); )

Formula

Column k of T^(j+1) = column j of T^(k+1) for j>=0, k>=0.

A138271 Triangle T, read by rows, where column k of T = column 0 of T^(k+1) for k>0, with column 0 of T = column 0 of T^4 shift right.

Original entry on oeis.org

1, 1, 1, 4, 2, 1, 28, 10, 3, 1, 268, 78, 18, 4, 1, 3164, 798, 156, 28, 5, 1, 43672, 9874, 1714, 268, 40, 6, 1, 682632, 141282, 22368, 3164, 420, 54, 7, 1, 11834536, 2273730, 333910, 43672, 5320, 618, 70, 8, 1, 224283416, 40400466, 5566728, 682632, 77720
Offset: 0

Views

Author

Paul D. Hanna, Mar 11 2008

Keywords

Examples

			Triangle T begins:
1;
1, 1;
4, 2, 1;
28, 10, 3, 1;
268, 78, 18, 4, 1;
3164, 798, 156, 28, 5, 1;
43672, 9874, 1714, 268, 40, 6, 1;
682632, 141282, 22368, 3164, 420, 54, 7, 1;
11834536, 2273730, 333910, 43672, 5320, 618, 70, 8, 1;
224283416, 40400466, 5566728, 682632, 77720, 8378, 868, 88, 9, 1; ...
where column k of T = column 0 of T^(k+1)
with column 0 of T = column 0 of T^4 shift right:
column 1 of T = column 0 of T^2;
column 2 of T = column 0 of T^3;
column 3 of T = column 0 of T^4.
Matrix square of T, T^2, begins:
1;
2, 1;
10, 4, 1;
78, 26, 6, 1;
798, 232, 48, 8, 1;
9874, 2578, 486, 76, 10, 1;
141282, 33764, 5888, 864, 110, 12, 1;
2273730, 503910, 82210, 11396, 1390, 150, 14, 1; ...
where column k of T^2 = column 1 of T^(k+1):
column 0 of T^2 = column 1 of T;
column 2 of T^2 = column 1 of T^3;
column 3 of T^2 = column 1 of T^4.
Matrix cube of T, T^3, begins:
1;
3, 1;
18, 6, 1;
156, 48, 9, 1;
1714, 486, 90, 12, 1;
22368, 5888, 1050, 144, 15, 1;
333910, 82210, 14046, 1908, 210, 18, 1;
5566728, 1289928, 211182, 28072, 3120, 288, 21, 1; ...
where column k of T^3 = column 2 of T^(k+1):
column 0 of T^3 = column 2 of T;
column 1 of T^3 = column 2 of T^2;
column 3 of T^3 = column 2 of T^4.
Matrix 4th power of T, T^4, begins:
1;
4, 1;
28, 8, 1;
268, 76, 12, 1;
3164, 864, 144, 16, 1;
43672, 11396, 1908, 232, 20, 1;
682632, 170000, 28072, 3520, 340, 24, 1;
11834536, 2814832, 454848, 57408, 5820, 468, 28, 1; ...
where column k of T^4 = column 3 of T^(k+1):
column 0 of T^4 = column 3 of T = column 0 of T shift left;
column 1 of T^4 = column 3 of T^2;
column 2 of T^4 = column 3 of T^3.
		

Crossrefs

Cf. columns: A138272, A138273, A138274; central terms: A138275; variants: A091351, A094587, A135902.

Programs

  • PARI
    {T(n, k) = if(k>n||k<0, 0, if(k==n, 1, if(k==0, T(n+2, 3), sum(j=0, n-k, T(n-k, j)*T(j+k-1, k-1))); ); )}
    for(n=0,10,for(k=0,n,print1(T(n,k),", "));print(""))
    
  • PARI
    /* Column k of T = column 0 of T^(k+1): */
    {T(n, k) = local(M=if(n==0,Mat(1),matrix(n,n,r,c,if(r>=c,T(r-1,c-1))))); if(k==n, 1, if(k==0, (M^4)[n, 1],(M^(k+1))[n-k+1, 1]))}
    for(n=0,10,for(k=0,n,print1(T(n,k),", "));print(""))

Formula

Column k of T^(j+1) = column j of T^(k+1) for j>=0, k>=0.

A104446 Square of triangular matrix A104445, read by rows, where X=A104445 satisfies: SHIFT_LEFT_UP(X) = X^2 - X + I.

Original entry on oeis.org

1, 2, 1, 3, 2, 1, 5, 5, 2, 1, 10, 13, 7, 2, 1, 25, 39, 25, 9, 2, 1, 78, 139, 100, 41, 11, 2, 1, 296, 587, 459, 205, 61, 13, 2, 1, 1330, 2897, 2418, 1149, 366, 85, 15, 2, 1, 6935, 16462, 14506, 7233, 2421, 595, 113, 17, 2, 1, 41352, 106301, 98161, 50905, 17706, 4535, 904
Offset: 0

Views

Author

Paul D. Hanna, Mar 08 2005

Keywords

Comments

Column 0: T(n,0) = 1 + A091352(n-1) for n>0. Column 1 is A104447. Row sums form A104448.

Examples

			Rows begin:
1;
2,1;
3,2,1;
5,5,2,1;
10,13,7,2,1;
25,39,25,9,2,1;
78,139,100,41,11,2,1;
296,587,459,205,61,13,2,1;
1330,2897,2418,1149,366,85,15,2,1
6935,16462,14506,7233,2421,595,113,17,2,1; ...
		

Crossrefs

Programs

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

Formula

T(n, k) = A104445(n, k) + A104445(n+1, k+1) - I(n, k), where I=identity matrix. T(n, k) = A091351(n-1, k) + A091351(n, k+1) - I(n, k), for n>k>=0.

A127420 Triangle, read by rows, where row n+1 is generated from row n by first inserting zeros at positions {(m+2)*(m+3)/2, m>=0} in row n and then taking the partial sums in reverse order, for n>=2, starting with 1's in the initial two rows.

Original entry on oeis.org

1, 1, 1, 2, 1, 1, 4, 2, 2, 1, 9, 5, 5, 3, 1, 1, 24, 15, 15, 10, 5, 5, 2, 1, 77, 53, 53, 38, 23, 23, 13, 8, 3, 3, 1, 295, 218, 218, 165, 112, 112, 74, 51, 28, 28, 15, 7, 4, 1, 1, 1329, 1034, 1034, 816, 598, 598, 433, 321, 209, 209, 135, 84, 56, 28, 28, 13, 6, 2, 1, 6934, 5605
Offset: 0

Views

Author

Paul D. Hanna, Jan 14 2007

Keywords

Comments

Column 0 forms A091352, which also equals column 1 of table A125781, where table A125781 is generated by a complementary recurrence of this triangle. The number of terms in row n is A127419(n).

Examples

			To generate row 6, start with row 5:
24, 15, 15, 10, 5, 5, 2, 1;
insert zeros at positions [1,4,8,13,..., (m+2)*(m+3)/2 - 2,...]:
24, 0, 15, 15, 0, 10, 5, 5, 0, 2, 1;
then row 6 equals the partial sums of row 5 taken in reverse order:
24, _0, 15, 15, _0, 10, _5, 5, 0, 2, 1;
77, 53, 53, 38, 23, 23, 13, 8, 3, 3, 1.
Triangle begins:
1;
1, 1;
2, 1, 1;
4, 2, 2, 1;
9, 5, 5, 3, 1, 1;
24, 15, 15, 10, 5, 5, 2, 1;
77, 53, 53, 38, 23, 23, 13, 8, 3, 3, 1;
295, 218, 218, 165, 112, 112, 74, 51, 28, 28, 15, 7, 4, 1, 1;
1329, 1034, 1034, 816, 598, 598, 433, 321, 209, 209, 135, 84, 56, 28, 28, 13, 6, 2, 1;
Column 0 of this triangle equals column 1 of triangle A091351, where triangle A091351 begins:
1;
1, 1;
1, 2, 1;
1, 4, 3, 1;
1, 9, 9, 4, 1;
1, 24, 30, 16, 5, 1;
1, 77, 115, 70, 25, 6, 1;
1, 295, 510, 344, 135, 36, 7, 1; ...
and column k of A091351 = row sums of matrix power A091351^k for k>=0.
		

Crossrefs

A098446 Triangle, read by rows, such that T(n,k) equals the k-th term of the convolution of the (n-1)-th diagonal with the k-th row of this triangle.

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 1, 3, 4, 1, 1, 4, 9, 9, 1, 1, 5, 16, 30, 24, 1, 1, 6, 25, 70, 115, 77, 1, 1, 7, 36, 135, 344, 510, 295, 1, 1, 8, 49, 231, 805, 1908, 2602, 1329, 1, 1, 9, 64, 364, 1616, 5325, 11904, 15133, 6934, 1, 1, 10, 81, 540, 2919, 12381, 39001, 83028, 99367, 41351, 1
Offset: 0

Views

Author

Paul D. Hanna, Sep 07 2004

Keywords

Comments

The rows of this triangle are the reverse of the rows of triangle A091351, in which the k-th column lists the row sums of the k-th matrix power of A091351. Row sums form A091352 and equal the secondary diagonal.

Examples

			T(7,3) = T(3,0)*T(6,3) + T(3,1)*T(5,2) + T(3,2)*T(4,1) + T(3,3)*T(3,0)
= 1*70 + 3*16 + 4*4 + 1*1 = 135.
Rows begin:
[1],
[1,1],
[1,2,1],
[1,3,4,1],
[1,4,9,9,1],
[1,5,16,30,24,1],
[1,6,25,70,115,77,1],
[1,7,36,135,344,510,295,1],
[1,8,49,231,805,1908,2602,1329,1],
[1,9,64,364,1616,5325,11904,15133,6934,1],...
		

Crossrefs

Programs

  • PARI
    T(n,k)=if(n
    				

Formula

T(n, k) = Sum_{i=0..k} T(k, i)*T(n-i-1, k-i) for 0

A098447 Triangle T, read by rows, such that diagonal n equals column 0 of T^(n+1), the (n+1)-th matrix power of T.

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 1, 3, 4, 1, 1, 4, 9, 9, 1, 1, 5, 16, 32, 24, 1, 1, 6, 25, 78, 150, 79, 1, 1, 7, 36, 155, 532, 1018, 340, 1, 1, 8, 49, 271, 1395, 5802, 10996, 2090, 1, 1, 9, 64, 434, 3036, 21343, 116658, 212434, 20613, 1, 1, 10, 81, 652, 5824, 60209, 661325, 5072504
Offset: 0

Author

Paul D. Hanna, Sep 07 2004

Keywords

Comments

Row sums form A098448.

Examples

			T(7,3) = T(3,0)*T(3,0) + T(3,1)*T(4,1) + T(3,2)*T(5,2) + T(3,3)*T(6,3)
= 1*1 + 3*4 + 4*16 + 1*78 = 155.
Rows of T begin:
[1],
[1,1],
[1,2,1],
[1,3,4,1],
[1,4,9,9,1],
[1,5,16,32,24,1],
[1,6,25,78,150,79,1],
[1,7,36,155,532,1018,340,1],
[1,8,49,271,1395,5802,10996,2090,1],
[1,9,64,434,3036,21343,116658,212434,20613,1],...
Matrix square T^2 begins:
[1],
[2,1],
[4,4,1],
[9,14,8,1],
[24,53,54,18,1],
[79,234,376,280,48,1],
[340,1291,2976,4034,2196,158,1],...
where column 0 is {1,2,4,9,24,79,340,...} and forms diagonal 1 of T.
Matrix cube T^3 begins:
[1],
[3,1],
[9,6,1],
[32,33,12,1],
[150,219,135,27,1],
[1018,2023,1944,744,72,1],...
where column 0 is {1,3,9,32,150,1018,...} and forms diagonal 2 of T.
		

Crossrefs

Programs

  • PARI
    T(n,k)=if(n
    				

Formula

T(n, k) = Sum_{i=0..k} T(k, i)*T(n-k+i-1, i), for 0
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