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 1-5 of 5 results.

A316842 Three-column table read by rows giving primitive integer sides of proper triangles (i,j,k) with i >= j >= k >= 1, j+k > i, gcd(i,j,k) = 1.

Original entry on oeis.org

1, 1, 1, 2, 2, 1, 3, 2, 2, 3, 3, 1, 3, 3, 2, 4, 3, 2, 4, 3, 3, 4, 4, 1, 4, 4, 3, 5, 3, 3, 5, 4, 2, 5, 4, 3, 5, 4, 4, 5, 5, 1, 5, 5, 2, 5, 5, 3, 5, 5, 4, 6, 4, 3, 6, 5, 2, 6, 5, 3, 6, 5, 4, 6, 5, 5, 6, 6, 1, 6, 6, 5, 7, 4, 4, 7, 5, 3, 7, 5, 4, 7, 5, 5, 7, 6, 2, 7, 6, 3, 7, 6, 4, 7, 6, 5, 7, 6, 6, 7, 7, 1, 7, 7, 2, 7, 7, 3, 7, 7, 4, 7, 7, 5, 7, 7, 6, 8, 5, 4
Offset: 1

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Author

N. J. A. Sloane, Jul 23 2018, following a suggestion from Donald S. McDonald

Keywords

Examples

			Table begins:
[1,1,1],
[2,2,1],
[3,2,2],
[3,3,1],
[3,3,2],
[4,3,2],
[4,3,3],
[4,4,1],
[4,4,3],
[5,3,3],
[5,4,2],
...
		

Crossrefs

There are A123323(k) rows that begin with k.
The three columns are A316846, A316847, A316848.
A316850 is a compressed version.
See A316841 for all triples (including imprimitive triples).
See A316852 and A317181 & A317183 for perimeter and area.
Other related sequences: A051493, A070080, A070081, A070082, A070110.

A316847 Column 2 of table A316842.

Original entry on oeis.org

1, 2, 2, 3, 3, 3, 3, 4, 4, 3, 4, 4, 4, 5, 5, 5, 5, 4, 5, 5, 5, 5, 6, 6, 4, 5, 5, 5, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 5, 5, 6, 6, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 5, 6, 6, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 6, 7, 7, 7, 7, 8, 8, 8, 9, 9, 9, 9, 9
Offset: 1

Views

Author

N. J. A. Sloane, Jul 23 2018

Keywords

Crossrefs

Extensions

Terms a(54) and beyond from Lars Blomberg, Jul 27 2018

A316848 Column 3 of table A316842.

Original entry on oeis.org

1, 1, 2, 1, 2, 2, 3, 1, 3, 3, 2, 3, 4, 1, 2, 3, 4, 3, 2, 3, 4, 5, 1, 5, 4, 3, 4, 5, 2, 3, 4, 5, 6, 1, 2, 3, 4, 5, 6, 4, 5, 3, 5, 2, 3, 4, 5, 6, 7, 1, 3, 5, 7, 5, 4, 5, 3, 4, 5, 6, 7, 2, 3, 4, 5, 6, 7, 8, 1, 2, 4, 5, 7, 8, 5, 4, 5, 6, 7, 3, 5, 7, 2, 3, 4, 5, 6
Offset: 1

Views

Author

N. J. A. Sloane, Jul 23 2018

Keywords

Crossrefs

Extensions

Terms a(54) and beyond from Lars Blomberg, Jul 27 2018

A316852 Consider primitive integer triangles as listed in rows of table A316842. Sequence gives perimeters of these triangles in the same order.

Original entry on oeis.org

3, 5, 7, 7, 8, 9, 10, 9, 11, 11, 11, 12, 13, 11, 12, 13, 14, 13, 13, 14, 15, 16, 13, 17, 15, 15, 16, 17, 15, 16, 17, 18, 19, 15, 16, 17, 18, 19, 20, 17, 18, 17, 19, 17, 18, 19, 20, 21, 22, 17, 19, 21, 23, 19, 19, 20, 19, 20, 21, 22, 23, 19, 20, 21, 22, 23, 24
Offset: 1

Views

Author

N. J. A. Sloane, Jul 23 2018

Keywords

Comments

The only missing numbers are 1,2,4,6.

Crossrefs

a(n) = A316846(n)+A316847(n)+A316848(n).

Extensions

Terms a(54) and beyond from Lars Blomberg, Jul 27 2018

A317181 Consider primitive integer triangles as listed in rows of table A316842. Sequence gives 16*area^2 for these triangles in the same order.

Original entry on oeis.org

3, 15, 63, 35, 128, 135, 320, 63, 495, 275, 231, 576, 975, 99, 384, 819, 1344, 455, 351, 896, 1575, 2304, 143, 2975, 735, 675, 1536, 2499, 495, 1280, 2295, 3456, 4655, 195, 768, 1683, 2880, 4275, 5760, 1071, 2304, 935, 3591, 663, 1728, 3135, 4800, 6615, 8448, 255, 2223, 5775, 10143
Offset: 1

Views

Author

N. J. A. Sloane, Jul 23 2018

Keywords

Crossrefs

Subsequence of A316853.

Formula

a(n) = 16*s*(s-a)*(s-b)*(s-c) where s = A316852(n)/2, and a,b,c are A316843(n), A316844(n), A316845(n).
Showing 1-5 of 5 results.