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 1-3 of 3 results.

A332360 Main diagonal of A332359.

Original entry on oeis.org

3, 10, 30, 82, 180, 374, 656, 1126, 1784, 2726, 3916, 5582, 7628, 10354, 13592, 17542, 22212, 28042, 34672, 42762, 51964, 62614, 74496, 88510, 104044, 121914, 141536, 163666, 187944, 215638, 245492, 279262, 316024, 356458, 399900, 447614, 498700, 555354, 615776, 681286
Offset: 1

Views

Author

N. J. A. Sloane, Feb 11 2020

Keywords

Crossrefs

Cf. A332359.

A332357 Consider a partition of the triangle with vertices (0, 0), (1, 0), (0, 1) by the lines a_1*x_1 + a_2*x_2 = 1, where (x_1, x_2) is in {1, 2,...,m} X {1, 2,...,n}, m >= 1, n >= 1. Triangle read by rows: T(m,n) = number of cells (both 3-sided and 4-sided) in the partition, for m >= n >= 1.

Original entry on oeis.org

1, 2, 5, 3, 9, 17, 4, 14, 28, 47, 5, 20, 41, 70, 105, 6, 27, 57, 99, 150, 215, 7, 35, 75, 131, 199, 286, 381, 8, 44, 96, 169, 258, 372, 497, 649, 9, 54, 119, 211, 323, 467, 625, 817, 1029, 10, 65, 145, 258, 396, 574, 769, 1006, 1268, 1563, 11, 77, 173, 309, 475, 689, 923, 1208, 1523, 1878, 2257
Offset: 1

Views

Author

N. J. A. Sloane, Feb 11 2020

Keywords

Examples

			Triangle begins:
1,
2, 5,
3, 9, 17,
4, 14, 28, 47,
5, 20, 41, 70, 105,
6, 27, 57, 99, 150, 215,
7, 35, 75, 131, 199, 286, 381,
8, 44, 96, 169, 258, 372, 497, 649,
9, 54, 119, 211, 323, 467, 625, 817, 1029,
10, 65, 145, 258, 396, 574, 769, 1006, 1268, 1563,
...
		

Crossrefs

Cf. A332350, A332352, A332354, A332359 (edges).
Main diagonal is A332358.

Programs

Formula

T(m,n) = A332354(m,n)+A332356(m,n).

A332361 Consider a partition of the triangle with vertices (0, 0), (1, 0), (0, 1) by the lines a_1*x_1 + a_2*x_2 = 1, where (x_1, x_2) is in {1, 2,...,m} X {1, 2,...,n}, m >= 1, n >= 1. Triangle read by rows: T(m,n) = number of vertices in the partition, for m >= n >= 1.

Original entry on oeis.org

3, 4, 6, 5, 9, 14, 6, 13, 22, 36, 7, 18, 31, 52, 76, 8, 24, 43, 74, 110, 160, 9, 31, 56, 97, 144, 210, 276, 10, 39, 72, 126, 188, 275, 363, 478, 11, 48, 89, 157, 235, 345, 456, 601, 756, 12, 58, 109, 193, 290, 427, 565, 745, 938, 1164, 13, 69, 130, 231, 347, 511, 675, 890, 1120, 1390, 1660
Offset: 1

Views

Author

N. J. A. Sloane, Feb 11 2020

Keywords

Examples

			Triangle begins:
3,
4, 6,
5, 9, 14,
6, 13, 22, 36,
7, 18, 31, 52, 76,
8, 24, 43, 74, 110, 160,
9, 31, 56, 97, 144, 210, 276,
10, 39, 72, 126, 188, 275, 363, 478,
11, 48, 89, 157, 235, 345, 456, 601, 756,
12, 58, 109, 193, 290, 427, 565, 745, 938, 1164,
...
		

Crossrefs

Main diagonal is A332362.

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;
    ct3 := proc(m,n) local i; global VR;
    if m=1 or n=1 then max(m,n) else VR(m,n,2)/2+m+n+1; fi; end; # A332354
    ct4 := proc(m,n) local i; global VR;
    if m=1 or n=1 then 0 else VR(m,n,1)/4-VR(m,n,2)/2-m/2-n/2-1; fi; end; # A332356
    ct := (m,n) -> ct3(m,n) + ct4(m,n); # A332357
    cte := proc(m,n) local i; global VR;
    if m=1 or n=1 then 2*max(m,n)+1 else VR(m,n,1)/2-VR(m,n,2)/4+m+n; fi; end; # A332359
    ctv := (m,n) -> cte(m,n) - ct(m,n) + 1; # A332361
    for m from 1 to 12 do lprint([seq(ctv(m,n),n=1..m)]); od:

Formula

T(m,n) = A332359(m,n) - A332357(m,n) + 1 (Euler's formula).
Showing 1-3 of 3 results.