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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A332369 Consider a partition of the plane (a_1,a_2) in R X R by the lines a_1*x_1 + a_2*x_2 = 1 for 0 <= x_1 <= m-1, 1 <= x_2 <= 1-1. The cells are (generalized) triangles and quadrilaterals. Triangle read by rows: T(m,n) = number of quadrilateral cells in the partition for m >= n >= 2.

Original entry on oeis.org

3, 6, 9, 11, 18, 35, 18, 27, 52, 77, 27, 42, 81, 122, 191, 38, 57, 108, 159, 248, 321, 51, 78, 147, 216, 335, 436, 591, 66, 99, 186, 273, 424, 551, 746, 941, 83, 126, 235, 346, 537, 698, 943, 1190, 1503, 102, 153, 284, 415, 642, 829, 1118, 1407, 1776, 2097, 123, 186, 345, 504, 777, 1002, 1349, 1696, 2139, 2528, 3047
Offset: 2

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Author

N. J. A. Sloane, Feb 12 2020

Keywords

Examples

			Triangle begins:
3,
6, 9,
11, 18, 35,
18, 27, 52, 77,
27, 42, 81, 122, 191,
38, 57, 108, 159, 248, 321,
51, 78, 147, 216, 335, 436, 591,
66, 99, 186, 273, 424, 551, 746, 941,
83, 126, 235, 346, 537, 698, 943, 1190, 1503,...
		

Crossrefs

For main diagonal see A332370.

Programs

A332353 Triangle read by rows: T(m,n) = Sum_{-m= n >= 1.

Original entry on oeis.org

0, 0, 0, 1, 2, 8, 2, 4, 14, 24, 3, 6, 22, 38, 60, 4, 8, 30, 52, 82, 112, 5, 10, 40, 70, 112, 154, 212, 6, 12, 50, 88, 142, 196, 270, 344, 7, 14, 62, 110, 178, 246, 340, 434, 548, 8, 16, 74, 132, 214, 296, 410, 524, 662, 800, 9, 18, 88, 158, 258, 358, 498, 638, 808, 978, 1196
Offset: 1

Views

Author

N. J. A. Sloane, Feb 10 2020

Keywords

Comments

This is the triangle in A332352, halved.

Examples

			Triangle begins:
0,
0, 0,
1, 2, 8,
2, 4, 14, 24,
3, 6, 22, 38, 60,
4, 8, 30, 52, 82, 112,
5, 10, 40, 70, 112, 154, 212,
6, 12, 50, 88, 142, 196, 270, 344,
7, 14, 62, 110, 178, 246, 340, 434, 548,
8, 16, 74, 132, 214, 296, 410, 524, 662, 800,
...
		

Crossrefs

The main diagonal is A177719.

Programs

  • Maple
    VR := proc(m,n,q) local a,i,j; a:=0;
    for i from -m+1 to m-1 do for j from -n+1 to n-1 do
    if gcd(i,j)=q then a:=a+(m-abs(i))*(n-abs(j)); fi; od: od: a; end;
    for m from 1 to 12 do lprint(seq(VR(m,n,2)/2,n=1..m),); od:
  • Mathematica
    A332353[m_,n_]:=Sum[If[GCD[i,j]==2,2(m-i)(n-j),0],{i,2,m-1,2},{j,2,n-1,2}]+If[n>2,m*n-2m,0]+If[m>2,m*n-2n,0];Table[A332353[m, n],{m,15},{n, m}] (* Paolo Xausa, Oct 18 2023 *)

A332363 Triangle read by rows: T(m,n) = number of unstable threshold functions (the function u_{0,1}(m,n) of Alekseyev et al. 2015) for m >= n >= 2.

Original entry on oeis.org

1, 2, 7, 3, 11, 19, 4, 18, 31, 51, 5, 24, 42, 69, 95, 6, 33, 59, 98, 135, 191, 7, 41, 74, 124, 172, 243, 311, 8, 52, 94, 158, 219, 310, 397, 507, 9, 62, 114, 191, 265, 376, 482, 615, 747, 10, 75, 138, 233, 325, 462, 593, 758, 921, 1135
Offset: 2

Views

Author

N. J. A. Sloane, Feb 11 2020

Keywords

Examples

			Triangle begins:
1,
2, 7,
3, 11, 19,
4, 18, 31, 51,
5, 24, 42, 69, 95,
6, 33, 59, 98, 135, 191,
7, 41, 74, 124, 172, 243, 311,
8, 52, 94, 158, 219, 310, 397, 507,
9, 62, 114, 191, 265, 376, 482, 615, 747,
10, 75, 138, 233, 325, 462, 593, 758, 921, 1135,
...
		

Crossrefs

Main diagonal is A332364.

Programs

  • Maple
    VQ := proc(m,n,q) local eps,a,i,j; eps := 10^(-6); a:=0;
    for i from ceil(-m+eps) to floor(m-eps) do
    for j from ceil(-n+eps) to floor(n-eps) do
    if gcd(i,j)=q then a:=a+(m-abs(i))*(n-abs(j)); fi; od: od: a; end;
    VS := proc(m,n) local a,i,j; a:=0;
    for i from 1 to m-1 do for j from 1 to n-1 do
    if gcd(i,j)=1 then a:=a+1; fi; od: od: a; end; # A331781
    u01:=(m,n) -> 2*VQ(m/2,n/2,1)+2-VS(m,n); # This sequence
    for m from 2 to 12 do lprint([seq(u01(m,n),n=2..m)]); od:

A332365 Triangle read by rows: T(m,n) = number of threshold functions (the function u_{0,2}(m,n) of Alekseyev et al. 2015) for m >= n >= 2.

Original entry on oeis.org

3, 6, 13, 9, 21, 33, 12, 30, 49, 73, 15, 40, 66, 99, 133, 18, 51, 85, 130, 177, 237, 21, 63, 106, 164, 224, 301, 381, 24, 76, 130, 202, 277, 374, 475, 593, 27, 90, 154, 241, 331, 448, 570, 713, 857, 30, 105, 182, 287, 395, 538, 687, 862, 1039, 1261, 33, 121, 211, 335, 462, 632, 808, 1016, 1226, 1489, 1757
Offset: 2

Views

Author

N. J. A. Sloane, Feb 11 2020

Keywords

Examples

			Triangle begins:
3,
6, 13,
9, 21, 33,
12, 30, 49, 73,
15, 40, 66, 99, 133,
18, 51, 85, 130, 177, 237,
21, 63, 106, 164, 224, 301, 381,
24, 76, 130, 202, 277, 374, 475, 593,
27, 90, 154, 241, 331, 448, 570, 713, 857,
...
		

Crossrefs

Main diagonal is A332366.

Programs

  • Maple
    VQ := proc(m,n,q) local eps,a,i,j; eps := 10^(-6); a:=0;
    for i from ceil(-m+eps) to floor(m-eps) do
    for j from ceil(-n+eps) to floor(n-eps) do
    if gcd(i,j)=q then a:=a+(m-abs(i))*(n-abs(j)); fi; od: od: a; end;
    VS := proc(m,n) local a,i,j; a:=0;
    for i from 1 to m-1 do for j from 1 to n-1 do
    if gcd(i,j)=1 then a:=a+1; fi; od: od: a; end; # A331781
    u02:=(m,n) -> VQ(m,n,2)+2-2*VQ(m/2,n/2,1)+VS(m,n); # This sequence
    for m from 2 to 12 do lprint([seq(u02(m,n),n=2..m)]); od:
Previous Showing 11-14 of 14 results.