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.

A120897 Row sums of triangle A120894 (cascadence of 1+x+x^2).

Original entry on oeis.org

1, 3, 10, 33, 106, 336, 1056, 3296, 10234, 31648, 97551, 299888, 919865, 2816291, 8608712, 26278538, 80120533, 244022331, 742525242, 2257527861, 6858558246, 20822959508, 63181453350, 191601205342, 580749971840, 1759465640586
Offset: 0

Views

Author

Paul D. Hanna, Jul 14 2006

Keywords

Crossrefs

Cf. A120894, A120895, A120896.

A120896 Central terms of triangle A120894 (cascadence of 1+x+x^2).

Original entry on oeis.org

1, 1, 2, 5, 10, 27, 73, 189, 518, 1413, 3857, 10707, 29804, 83365, 234665, 662654, 1878059, 5341302, 15231940, 43552610, 124829236, 358537455, 1031835260, 2974872009, 8590929683, 24847042484, 71964879243, 208704926659
Offset: 0

Views

Author

Paul D. Hanna, Jul 14 2006

Keywords

Crossrefs

Cf. A120894, A120895, A120897.

A092683 Triangle, read by rows, such that the convolution of each row with {1,1} produces a triangle which, when flattened, equals this flattened form of the original triangle.

Original entry on oeis.org

1, 1, 1, 2, 1, 2, 3, 3, 2, 3, 6, 5, 5, 3, 6, 11, 10, 8, 9, 6, 11, 21, 18, 17, 15, 17, 11, 21, 39, 35, 32, 32, 28, 32, 21, 39, 74, 67, 64, 60, 60, 53, 60, 39, 74, 141, 131, 124, 120, 113, 113, 99, 113, 74, 141, 272, 255, 244, 233, 226, 212, 212, 187, 215, 141, 272, 527, 499
Offset: 0

Views

Author

Paul D. Hanna, Mar 04 2004

Keywords

Comments

First column and main diagonal forms A092684. Row sums form A092685.
This triangle is the cascadence of binomial (1+x). More generally, the cascadence of polynomial F(x) of degree d, F(0)=1, is a triangle with d*n+1 terms in row n where the g.f. of the triangle, A(x,y), is given by: A(x,y) = ( x*H(x) - y*H(x*y^d) )/( x*F(y) - y ), where H(x) satisfies: H(x) = G*H(x*G^d)/x and G=G(x) satisfies: G(x) = x*F(G(x)) so that G = series_reversion(x/F(x)); also, H(x) is the g.f. of column 0. - Paul D. Hanna, Jul 17 2006

Examples

			Rows begin:
1;
1, 1;
2, 1, 2;
3, 3, 2, 3;
6, 5, 5, 3, 6;
11, 10, 8, 9, 6, 11;
21, 18, 17, 15, 17, 11, 21;
39, 35, 32, 32, 28, 32, 21, 39;
74, 67, 64, 60, 60, 53, 60, 39, 74;
141, 131, 124, 120, 113, 113, 99, 113, 74, 141;
272, 255, 244, 233, 226, 212, 212, 187, 215, 141, 272;
527, 499, 477, 459, 438, 424, 399, 402, 356, 413, 272, 527;
1026, 976, 936, 897, 862, 823, 801, 758, 769, 685, 799, 527, 1026; ...
The convolution of each row with {1,1} gives the triangle:
1, 1;
1, 2, 1;
2, 3, 3, 2;
3, 6, 5, 5, 3;
6, 11, 10, 8, 9, 6;
11, 21, 18, 17, 15, 17, 11;
21, 39, 35, 32, 32, 28, 32, 21;
39, 74, 67, 64, 60, 60, 53, 60, 39; ...
which, when flattened, equals the original triangle in flattened form.

Links

Crossrefs

Cf. A092684, A092685, A092686, A092689, A120894, A120898.

Programs

  • PARI
    T(n,k)=if(n<0 || k>n,0, if(n==0 && k==0,1, if(n==1 && k<=1,1, if(k==n,T(n,0), T(n-1,k)+T(n-1,k+1)))))
for(n=0, 10, for(k=0, n, print1(T(n, k), ", ")); print(""))
  • PARI
    /* Generate Triangle by G.F. where F=1+x: */
{T(n,k)=local(A,F=1+x,d=1,G=x,H=1+x,S=ceil(log(n+1)/log(d+1))); for(i=0,n,G=x*subst(F,x,G+x*O(x^n)));for(i=0,S,H=subst(H,x,x*G^d+x*O(x^n))*G/x); A=(x*H-y*subst(H,x,x*y^d +x*O(x^n)))/(x*subst(F,x,y)-y); polcoeff(polcoeff(A,n,x),k,y)}
for(n=0, 10, for(k=0, n, print1(T(n, k), ", ")); print()) \\ Paul D. Hanna, Jul 17 2006

Formula

T(n, k) = T(n-1, k) + T(n-1, k+1) for 0<=k
G.f.: A(x,y) = ( x*H(x) - y*H(x*y) )/( x*(1+y) - y ), where H(x) satisfies: H(x) = H(x^2/(1-x))/(1-x) and H(x) is the g.f. of column 0 (A092684). - Paul D. Hanna, Jul 17 2006

A092686 Triangle, read by rows, such that the convolution of each row with {1,2} produces a triangle which, when flattened, equals this flattened form of the original triangle.

Original entry on oeis.org

1, 2, 2, 6, 4, 6, 16, 14, 12, 16, 46, 40, 40, 32, 46, 132, 120, 112, 110, 92, 132, 384, 352, 334, 312, 316, 264, 384, 1120, 1038, 980, 940, 896, 912, 768, 1120, 3278, 3056, 2900, 2776, 2704, 2592, 2656, 2240, 3278, 9612, 9012, 8576, 8256, 8000, 7840, 7552, 7758
Offset: 0

Views

Author

Paul D. Hanna, Mar 04 2004

Keywords

Comments

First column and main diagonal forms A092687. Row sums form A092688.
This triangle is the cascadence of binomial (1+2x). More generally, the cascadence of polynomial F(x) of degree d, F(0)=1, is a triangle with d*n+1 terms in row n where the g.f. of the triangle, A(x,y), is given by: A(x,y) = ( x*H(x) - y*H(x*y^d) )/( x*F(y) - y ), where H(x) satisfies: H(x) = G*H(x*G^d)/x and G=G(x) satisfies: G(x) = x*F(G(x)) so that G = series_reversion(x/F(x)); also, H(x) is the g.f. of column 0. - Paul D. Hanna, Jul 17 2006

Examples

			Rows begin:
1;
2, 2;
6, 4, 6;
16, 14, 12, 16;
46, 40, 40, 32, 46;
132, 120, 112, 110, 92, 132;
384, 352, 334, 312, 316, 264, 384;
1120, 1038, 980, 940, 896, 912, 768, 1120;
3278, 3056, 2900, 2776, 2704, 2592, 2656, 2240, 3278;
9612, 9012, 8576, 8256, 8000, 7840, 7552, 7758, 6556, 9612;
28236, 26600, 25408, 24512, 23840, 23232, 22862, 22072, 22724, 19224, 28236; ...
Convolution of each row with {1,2} results in the triangle:
1, 2;
2, 6, 4;
6, 16, 14, 12;
16, 46, 40, 40, 32;
46, 132, 120, 112, 110, 92;
132, 384, 352, 334, 312, 316, 264;
384, 1120, 1038, 980, 940, 896, 912, 768; ...
which, when flattened, equals the original triangle in flattened form.

Links

Crossrefs

Cf. A092683, A092687, A092688, A092689, A120894, A120898.

Programs

  • PARI
    T(n,k)=if(n<0 || k>n,0, if(n==0 && k==0,1, if(n==1 && k<=1,2, if(k==n,T(n,0), 2*T(n-1,k)+T(n-1,k+1)))))
for(n=0, 10, for(k=0, n, print1(T(n, k), ", ")); print(""))
  • PARI
    /* Generate Triangle by the G.F.: */
{T(n,k)=local(A,F=1+2*x,d=1,G=x,H=1+2*x,S=ceil(log(n+1)/log(d+1))); for(i=0,n,G=x*subst(F,x,G+x*O(x^n)));for(i=0,S,H=subst(H,x,x*G^d+x*O(x^n))*G/x); A=(x*H-y*subst(H,x,x*y^d +x*O(x^n)))/(x*subst(F,x,y)-y); polcoeff(polcoeff(A,n,x),k,y)}
for(n=0, 10, for(k=0, n, print1(T(n, k), ", ")); print()) \\ Paul D. Hanna, Jul 17 2006

Formula

T(n, k) = 2*T(n-1, k) + T(n-1, k+1) for 0<=k
G.f.: A(x,y) = ( x*H(x) - y*H(x*y) )/( x*(1+2y) - y ), where H(x) satisfies: H(x) = H(x^2/(1-2x))/(1-2x) and H(x) is the g.f. of column 0 (A092687). - Paul D. Hanna, Jul 17 2006

A120898 Cascadence of 1+2x+x^2; a triangle, read by rows of 2n+1 terms, that retains its original form upon convolving each row with [1,2,1] and then letting excess terms spill over from each row into the initial positions of the next row such that only 2n+1 terms remain in row n for n>=0.

Original entry on oeis.org

1, 2, 1, 2, 5, 6, 5, 2, 5, 16, 22, 18, 14, 12, 5, 16, 54, 78, 72, 58, 43, 38, 37, 16, 54, 186, 282, 280, 231, 182, 156, 128, 123, 124, 54, 186, 654, 1030, 1073, 924, 751, 622, 535, 498, 425, 418, 426, 186, 654, 2338, 3787, 4100, 3672, 3048, 2530, 2190, 1956, 1766
Offset: 0

Views

Author

Paul D. Hanna, Jul 14 2006

Keywords

Comments

In this case, the g.f. of column 0, H(x), satisfies: H(x) = H(x*G^2)*G/x where G satisfies: G = x*(1+2G+G^2), so that 1+G = g.f. of Catalan numbers (A000108). More generally, the cascadence of polynomial F(x) of degree d, F(0)=1, is a triangle with d*n+1 terms in row n where the g.f. H(x) of column 0 satisfies: H(x) = H(x*G^d)*G/x where G = x*F(G); thus G = series_reversion(x/F(x)), or, equivalently, [x^n] G = [x^n] x*F(x)^n/n for n>=1.
Further, the g.f. of the cascadence triangle for polynomial F(x) of degree d is given by: A(x,y) = ( x*H(x) - y*H(x*y^d) )/( x*F(y) - y ), where H(x) = G*H(x*G^d)/x and G = x*F(G). - Paul D. Hanna, Jul 17 2006

Examples

			Triangle begins:
1;
2, 1, 2;
5, 6, 5, 2, 5;
16, 22, 18, 14, 12, 5, 16;
54, 78, 72, 58, 43, 38, 37, 16, 54;
186, 282, 280, 231, 182, 156, 128, 123, 124, 54, 186;
654, 1030, 1073, 924, 751, 622, 535, 498, 425, 418, 426, 186, 654;
2338, 3787, 4100, 3672, 3048, 2530, 2190, 1956, 1766, 1687, 1456, 1452, 1494, 654, 2338; ...
Convolution of [1,2,1] with each row produces:
[1,2,1]*[1] = [1,2,1];
[1,2,1]*[2,1,2] = [2,5,6,5,2];
[1,2,1]*[5,6,5,2,5] = [5,16,22,18,14,12,5];
[1,2,1]*[16,22,18,14,12,5,16] = [16,54,78,72,58,43,38,37,16];
These convoluted rows, when concatenated, yield the sequence:
1,2,1, 2,5,6,5,2, 5,16,22,18,14,12,5, 16,54,78,72,58,43,38,37,16, ...
which equals the concatenated rows of this original triangle:
1, 2,1,2, 5,6,5,2,5, 16,22,18,14,12,5,16, 54,78,72,58,43,38,37,16,54,

Links

Crossrefs

Cf. A120899 (column 0), A120901 (central terms), A120902 (row sums), A000108 (Catalan); variants: A092683, A092686, A120894.

Programs

  • PARI
    T(n,k)=if(2*n
  • PARI
    /* Generated by the G.F.: */
{T(n,k)=local(A,F=1+2*x+x^2,d=2,G=x,H=1+x,S=ceil(log(n+1)/log(d+1))); for(i=0,n,G=x*subst(F,x,G+x*O(x^n)));for(i=0,S,H=subst(H,x,x*G^d+x*O(x^n))*G/x); A=(x*H-y*subst(H,x,x*y^d +x*O(x^n)))/(x*subst(F,x,y)-y); polcoeff(polcoeff(A,n,x),k,y)}
for(n=0, 10, for(k=0, 2*n, print1(T(n, k), ", ")); print()) \\ Paul D. Hanna, Jul 17 2006

Formula

G.f.: A(x,y) = ( x*H(x) - y*H(x*y^2) )/( x*F(y) - y ), where H(x) = G*H(x*G^2)/x, G = x*F(G), F(x)=1+2x+x^2. - Paul D. Hanna, Jul 17 2006

A120895 G.f. satisfies: A(x) = G(x)*A(x^3*G(x)^2) where G(x) is the g.f. of the Motzkin numbers (A001006).

Original entry on oeis.org

1, 1, 2, 5, 12, 30, 78, 206, 552, 1498, 4105, 11340, 31541, 88237, 248076, 700478, 1985397, 5646129, 16104378, 46056513, 132031176, 379315946, 1091890772, 3148736064, 9095091878, 26310816944, 76219704957, 221085782559, 642058752476, 1866693825362, 5432795508417
Offset: 0

Views

Author

Paul D. Hanna, Jul 14 2006

Keywords

Comments

Equals column 0 and main diagonal of triangle A120894 (cascadence of 1+x+x^2).

Examples

			A(x) = 1 + x + 2*x^2 + 5*x^3 + 12*x^4 + 30*x^5 + 78*x^6 + 206*x^7+...
= G(x)*A(x^3*G(x)^2) where
G(x) = 1 + x + 2*x^2 + 4*x^3 + 9*x^4 + 21*x^5 + 51*x^6 + 127*x^7 +...
is the g.f. of the Motzkin numbers (A001006) so that G(x) satisfies:
G(x) = 1 + x*G(x) + x^2*G(x)^2.

Crossrefs

Cf. A120894, A120896, A120897; A001006; variants: A092684, A092687, A120899.

Programs

  • PARI
    {a(n)=local(A=1+x,G=1/x*serreverse(x/(1+x+x^2+x*O(x^n)))); for(i=0,n,A=G*subst(A,x,x^3*G^2 +x*O(x^n)));polcoeff(A,n,x)}

A120919 Cascadence of (1+x)^3; a triangle, read by rows of 3n+1 terms, that retains its original form upon convolving each row with [1,3,3,1] and then letting excess terms spill over from each row into the initial positions of the next row such that only 3n+1 terms remain in row n for n>=0.

Original entry on oeis.org

1, 3, 3, 1, 3, 12, 19, 18, 15, 10, 3, 12, 55, 111, 138, 128, 96, 66, 55, 39, 12, 55, 276, 636, 930, 1005, 876, 669, 498, 360, 263, 240, 177, 55, 276, 1464, 3666, 5979, 7317, 7242, 6138, 4737, 3506, 2607, 2046, 1569, 1212, 1170, 883, 276, 1464, 8058, 21369, 37716
Offset: 0

Views

Author

Paul D. Hanna, Jul 17 2006

Keywords

Examples

			Triangle begins:
1;
3, 3, 1, 3;
12, 19, 18, 15, 10, 3, 12;
55, 111, 138, 128, 96, 66, 55, 39, 12, 55;
276, 636, 930, 1005, 876, 669, 498, 360, 263, 240, 177, 55, 276;
Convolution of [1,3,3,1] with each row produces:
[1,3,3,1]*[1] = [1,3,3,1];
[1,3,3,1]*[3,3,1,3] = [3,12,19,18,15,10,3];
[1,3,3,1]*[12,19,18,15,10,3,12] = [12,55,111,138,128,96,66,55,39,12];
[1,3,3,1]*[55,111,138,128,96,66,55,39,12,55] =
[55,276,636,930,1005,876,669,498,360,263,240,177,55];
These convoluted rows, when concatenated, yield the sequence:
1,3,3,1, 3,12,19,18,15,10,3, 12,55,111,138,128,96,66,55,39,12, 55,...
which equals the concatenated rows of this original triangle:
1, 3,3,1,3, 12,19,18,15,10,3,12, 55,111,138,128,96,66,55,39,12,55, ...

Crossrefs

Cf. A120920 (column 0), A120922 (central terms), A120923 (row sums), A001764 (ternary trees); variants: A092683, A092686, A120894, A120898, A120919.

Programs

  • Mathematica
    T[n_, k_] := T[n, k] = If[3*n < k || k < 0, 0, If[n == 0 && k == 0, 1, If[k == 3*n, T[n, 0], T[n - 1, k + 1] + 3*T[n - 1, k] + 3*T[n - 1, k - 1] + T[n - 1, k - 2]]]];
Table[T[n, k], {n, 0, 10}, {k, 0, 3 n}] // Flatten (* Jean-François Alcover, Jan 24 2018, translated from PARI *)
  • PARI
    /* Generate Triangle by the Recurrence: */
{T(n,k)=if(3*n
  • PARI
    /* Generate Triangle by the G.F.: */
{T(n,k)=local(A,F=(1+x)^3,d=3,G=x,H=1+x,S=ceil(log(n+1)/log(d+1))); for(i=0,n,G=x*subst(F,x,G+x*O(x^n)));for(i=0,S,H=subst(H,x,x*G^d+x*O(x^n))*G/x); A=(x*H-y*subst(H,x,x*y^d +x*O(x^n)))/(x*subst(F,x,y)-y); polcoeff(polcoeff(A,n,x),k,y)}
for(n=0, 10, for(k=0, 3*n, print1(T(n, k), ", ")); print(""))

Formula

G.f.: A(x,y) = ( x*H(x) - y*H(x*y^3) )/( x*(1+y)^3 - y ), where H(x) satisfies: H(x) = G*H(x^4*G^3) and G(x) is g.f. of A001764: G(x) = 1 + x*G(x)^3.

A120914 Cascadence of (1+2x)^2; a triangle, read by rows of 2n+1 terms, that retains its original form upon convolving each row with [1,4,4] and then letting excess terms spill over from each row into the initial positions of the next row such that only 2n+1 terms remain in row n for n>=0.

Original entry on oeis.org

1, 4, 4, 4, 20, 36, 32, 16, 20, 116, 256, 288, 212, 144, 80, 116, 720, 1776, 2388, 2144, 1504, 1012, 784, 464, 720, 4656, 12372, 18800, 19632, 15604, 10848, 7648, 5712, 4736, 2880, 4656, 30996, 86912, 144320, 169332, 151792, 113456, 79696, 58176
Offset: 0

Views

Author

Paul D. Hanna, Jul 17 2006

Keywords

Comments

More generally, the cascadence of polynomial F(x) of degree d, F(0)=1, is a triangle with d*n+1 terms in row n where the g.f. of the triangle, A(x,y), is given by: A(x,y) = ( x*H(x) - y*H(x*y^d) )/( x*F(y) - y ), where H(x) satisfies: H(x) = G*H(x*G^d)/x and G satisfies: G = x*F(G) so that G = series_reversion(x/F(x)); also, H(x) is the g.f. of column 0.

Examples

			Triangle begins:
1;
4, 4, 4;
20, 36, 32, 16, 20;
116, 256, 288, 212, 144, 80, 116;
720, 1776, 2388, 2144, 1504, 1012, 784, 464, 720;
4656, 12372, 18800, 19632, 15604, 10848, 7648, 5712, 4736, 2880, 4656;
Convolution of [1,4,4] with each row produces:
[1,4,4]*[1] = [1,4,4];
[1,4,4]*[4,4,4] = [4,20,36,32,16];
[1,4,4]*[20,36,32,16,20] = [20,116,256,288,212,144,80];
[1,4,4]*[116,256,288,212,144,80,116] =
[116,720,1776,2388,2144,1504,1012,784,464];
These convoluted rows, when concatenated, yield the sequence:
1,4,4, 4,20,36,32,16, 20,116,256,288,212,144,80, 116,720,1776,2388,...
which equals the concatenated rows of this original triangle:
1, 4,4,4, 20,36,32,16,20, 116,256,288,212,144,80,116, 720,1776,2388,...

Crossrefs

Cf. A120915 (column 0), A120917 (central terms), A120918 (row sums), A000108 (Catalan); variants: A092683, A092686, A120894, A120898, A120919.

Programs

  • PARI
    /* Generate Triangle by the Recurrence: */
{T(n,k)=if(2*n
  • PARI
    /* Generate Triangle by the G.F.: */
{T(n,k)=local(A,F=1+4*x+4*x^2,d=2,G=x,H=1+x,S=ceil(log(n+1)/log(d+1))); for(i=0,n,G=x*subst(F,x,G+x*O(x^n)));for(i=0,S,H=subst(H,x,x*G^d+x*O(x^n))*G/x); A=(x*H-y*subst(H,x,x*y^d +x*O(x^n)))/(x*subst(F,x,y)-y); polcoeff(polcoeff(A,n,x),k,y)}
for(n=0,10,for(k=0,n,print1(T(n,k),", "));print(""))

Formula

G.f.: A(x,y) = ( x*H(x) - y*H(x*y^2) )/( x*(1+2y)^2 - y ), where H(x) satisfies: H(x) = G*H(x*G^2)/x and G satisfies: G = x*(1 + 2G)^2 ; also, H(x) is the g.f. of column 0.
Showing 1-8 of 8 results.

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