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.

A080819 Row sums from triangle in A080818.

Original entry on oeis.org

1, 4, 9, 16, 16, 25, 36, 36, 49, 64, 81, 81, 100, 121, 121, 144, 169, 196, 196, 225, 256, 256, 289, 324, 361, 361, 400, 441, 441, 484, 529, 529, 576, 625, 676, 676, 729, 784, 784, 841, 900, 961, 961, 1024, 1089, 1089, 1156, 1225, 1225, 1296, 1369, 1444, 1444
Offset: 1

Views

Author

Amarnath Murthy, Mar 21 2003

Keywords

Crossrefs

Cf. A080817, A080818, A080820.

Programs

  • Maple
    seq((ceil(sqrt(n*(n+1)/2)))^2,n=1..60); # C. Ronaldo

Formula

a(n) = (ceiling(sqrt(n*(n+1)/2)))^2. - C. Ronaldo (aga_new_ac(AT)hotmail.com), Dec 19 2004

Extensions

More terms from C. Ronaldo (aga_new_ac(AT)hotmail.com), Dec 19 2004

A080817 Leading diagonal of triangle in A080818.

Original entry on oeis.org

1, 3, 6, 10, 6, 10, 15, 8, 13, 19, 26, 15, 22, 30, 16, 24, 33, 43, 25, 35, 46, 25, 36, 48, 61, 36, 49, 63, 35, 49, 64, 33, 48, 64, 81, 46, 63, 81, 43, 61, 80, 100, 58, 78, 99, 54, 75, 97, 49, 71, 94, 118, 66, 90, 115, 60, 85, 111, 138, 79, 106, 134, 72, 100, 129, 159, 93, 123
Offset: 1

Views

Author

Amarnath Murthy, Mar 21 2003

Keywords

Crossrefs

Cf. A080818, A080819, A080820.

Formula

From David Wasserman, May 13 2004: (Start)
a(n) = (ceiling(sqrt(n(n+1)/2)))^2 - n(n-1)/2.
a(n) = A048761(A000217(n)) - A000217(n-1). (End)

Extensions

More terms from David Wasserman, May 13 2004

A080818 Triangle read by rows in which the n-th row contains n distinct numbers whose sum is the smallest square.

Original entry on oeis.org

1, 1, 3, 1, 2, 6, 1, 2, 3, 10, 1, 2, 3, 4, 6, 1, 2, 3, 4, 5, 10, 1, 2, 3, 4, 5, 6, 15, 1, 2, 3, 4, 5, 6, 7, 8, 1, 2, 3, 4, 5, 6, 7, 8, 13, 1, 2, 3, 4, 5, 6, 7, 8, 9, 19, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 26, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 15, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 22, 1, 2, 3, 4, 5, 6, 7, 8
Offset: 1

Views

Author

Amarnath Murthy, Mar 21 2003

Keywords

Comments

If n(n+1)/2 is a square triangular number then the n-th row contains first n natural numbers (e.g., the 8th row).

Examples

			1; 1,3; 1,2,6; 1,2,3,10; 1,2,3,4,6; 1,2,3,4,5,10; 1,2,3,4,5,6,15; 1,2,3,4,5,6,...

Crossrefs

Cf. A080817, A080819, A080820.

Programs

  • Maple
    seq(op([seq(i,i=1..n-1),(ceil(sqrt(n*(n+1)/2)))^2 - n*(n-1)/2]),n=1..15); # C. Ronaldo

Extensions

More terms from C. Ronaldo (aga_new_ac(AT)hotmail.com), Dec 19 2004
Showing 1-3 of 3 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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