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.

A183232 Second of two complementary trees generated by the triangular numbers. The other tree is A183231.

Original entry on oeis.org

2, 8, 5, 53, 12, 26, 9, 1538, 63, 103, 17, 404, 33, 64, 14, 1186568, 1593, 2143, 74, 5563, 117, 188, 23, 82619, 432, 628, 41, 2209, 75, 134, 20, 703974775733, 1188108, 1272808, 1649, 2301583, 2208, 2924, 86, 15487393
Offset: 1

Views

Author

Clark Kimberling, Jan 02 2011

Keywords

Comments

See A183231 (first tree).

Examples

			First 3 levels:
....................2
...............8...........5
............53...12.....26...9
		

Crossrefs

Formula

See the formulas at A183231 and A183244.

A183233 Ordering of the numbers in the tree A183231; complement of A183234.

Original entry on oeis.org

1, 3, 4, 6, 7, 10, 11, 13, 15, 16, 18, 19, 21, 22, 24, 25, 28, 29, 31, 32, 34, 36, 37, 39, 40, 42, 43, 45, 46, 48, 49, 51, 52, 55, 56, 58, 59, 61, 62, 66, 67, 69, 70, 72, 73, 76, 78, 79, 81, 82, 84, 85, 88, 89, 91, 92, 94, 95, 97, 98, 101, 102, 105, 106, 108, 109, 111, 112, 115, 116, 118, 120, 121, 123, 124, 126, 127, 130, 131, 133, 136, 137, 139, 140, 142, 143, 146, 147, 149, 151, 153, 154, 156, 157, 159, 160, 163, 164, 166, 168, 169, 171, 172, 174, 175, 177, 178, 181, 182, 184, 186
Offset: 1

Views

Author

Clark Kimberling, Jan 02 2011

Keywords

Crossrefs

Programs

  • Mathematica
      nn=200; t={1}; t0=t; While[t=Select[Union[t,(1/2)*(t^2+5t+2), t+Floor[1/2+(2t+4)^(1/2)]], #<=nn &]; t0 !=t, t0=t]; t
    f[s_List] := Select[ Union@ Join[s, (s^2 + 5 s + 2)/2, s + Floor[1/2 + Sqrt@ (2 s + 4)]], # < 201 &]; NestWhile[f, {1}, UnsameQ, All]

Formula

The monotonic ordering of the numbers in the set S generated by these rules: 1 is in S, and if n is in S, then (n^2+5n+2)/2 and n+Floor(1/2+sqrt(2n+4)) are in S.

A183420 First of two complementary trees generated by the squares; the other tree is A183421.

Original entry on oeis.org

2, 14, 4, 254, 18, 34, 6, 65534, 270, 398, 22, 1294, 40, 62, 9, 4294967294, 65790, 73982, 286, 159998, 418, 574, 27, 1679614, 1330, 1762, 46, 4094, 70, 119, 12
Offset: 1

Views

Author

Clark Kimberling, Jan 04 2011

Keywords

Comments

Begin with the main tree A183169 generated by the squares:
......................1
......................2
...........4.....................3
.......16.......6...........9..........5
...256...20...36..8......81...12....25...7
Every n>2 is in the subtree from 4 or the subtree from 3. Therefore, on subtracting 2 from all entries of those subtrees, we obtain complementary trees: A183420 and A183421.

Examples

			First three levels:
..................2
.............14.........4
..........254...18....34...6
		

Crossrefs

Cf. A183169, A183420, A183421, A183422, A183231 (analogous trees generated by the triangular numbers).

Formula

See the formulas at A183169 and A183422.
Showing 1-3 of 3 results.