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 1-4 of 4 results.

A136601 Complement of A136602.

Original entry on oeis.org

211, 219, 221, 227, 229, 233, 235, 239, 241, 247, 277, 284, 286, 287, 300, 302, 310, 377, 388, 390, 395, 397, 400, 403, 404, 406, 413, 469, 485, 487, 493, 494, 499, 505, 507, 508, 512, 518, 526, 559, 575, 593, 598, 607, 608, 611, 613, 616, 632, 635, 665
Offset: 1

Views

Author

Reinhard Zumkeller, Jan 12 2008

Keywords

Comments

A066957(a(n)) = 0.

A066957 a(n) = number of ways of placing '+' and '-' among the digits 123456789 so that the result of the expression is n, '-' before 1 IS allowed.

Original entry on oeis.org

22, 43, 18, 41, 18, 40, 24, 39, 18, 46, 17, 38, 27, 38, 24, 43, 18, 39, 23, 37, 23, 43, 25, 36, 32, 36, 25, 44, 25, 35, 34, 31, 26, 37, 24, 35, 32, 32, 27, 37, 31, 26, 34, 34, 29, 42, 27, 27, 35, 26, 28, 35, 29, 33, 30, 26, 23, 29, 32, 25, 33, 30, 24, 34, 22, 26, 32, 30, 25
Offset: 0

Views

Author

Miklos SZABO (mike(AT)ludens.elte.hu), Feb 01 2002

Keywords

Comments

A066957(9)=46 is the largest term; A066957(456789)=2 is the last term greater than 1; a(n)=0 for n>123456789; 1715 terms are greater than 0; a(A136601(n))=0; a(A136602(n))>0; a(A136603(n))=1; partial sums are A136604. - Reinhard Zumkeller, Jan 12 2008

Crossrefs

Cf. A066956.

A136603 Positive numbers having a unique representation by inserting minus and plus-signs in 123456789.

Original entry on oeis.org

176, 191, 194, 196, 209, 213, 215, 217, 223, 237, 253, 259, 263, 272, 274, 275, 289, 290, 292, 293, 295, 305, 307, 308, 353, 361, 367, 379, 380, 381, 382, 386, 392, 399, 401, 405, 415, 416, 418, 419, 427, 443, 461, 463, 467, 475, 477, 479, 481, 490, 491
Offset: 1

Views

Author

Reinhard Zumkeller, Jan 12 2008

Keywords

Comments

A066957(a(n)) = 1; subsequence of A136601;
the sequence is finite with 869 terms.

Examples

			a(1) = 176 = 1 - 2 + 34 + 56 + 78 + 9;
a(2) = 191 = 123 + 4 + 56 + 7 - 8 + 9;
a(3) = 194 = 1 - 2 + 34 + 5 + 67 + 89;
a(4) = 196 = -1 + 2 + 34 + 5 + 67 + 89;
a(5) = 209 = 1 + 234 + 56 + 7 - 89;
a(6) = 213 = 123 + 4 + 5 - 6 + 78 + 9;
a(7) = 215 = 123 + 4 - 5 + 6 + 78 + 9;
a(8) = 217 = 123 - 4 + 5 + 6 + 78 + 9;
a(9) = 223 = -1 + 23 + 45 + 67 + 89;
a(10) = 237 = -123 + 456 - 7 - 89;
a(11) = 253 = -1 + 2 + 345 - 6 - 78 - 9;
a(12) = 259 = -1 + 234 - 56 - 7 + 89;
a(869) = 123456789 = A136602(1715).
		

A373301 Sum of successive nonnegative integers in a row of length p(n) where p counts integer partitions.

Original entry on oeis.org

0, 3, 12, 40, 98, 253, 540, 1199, 2415, 4893, 9268, 17864, 32421, 59265, 104632, 184338, 315414, 540155, 901845, 1504173, 2461932, 4013511, 6443170, 10314675, 16281749, 25608450, 39838855, 61716941, 94682665, 144726102
Offset: 1

Views

Author

Olivier Gérard, May 31 2024

Keywords

Comments

The length of each row is given by A000041.
As many sequences start like the nonnegative integers, their row sums when disposed in this shape start with the same values.
Here is a sample list by A-number order of the sequences which are sufficiently close to A001477 to have the same row sums for at least 8 terms: A089867, A089868, A089869, A089870, A118760, A123719, A130696, A136602, A254109, A258069, A258070, A258071, A266279, A272813, A273885, A273886, A273887, A273888.

Examples

			Illustration of the first few terms
.
0   | 0
3   | 1,  2
12  | 3,  4,  5
40  | 6,  7,  8,  9,  10
98  | 11, 12, 13, 14, 15, 16, 17
253 | 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28
540 | 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43
.
		

Crossrefs

Cf. A373300, original version, with positive integers A000027.
Cf. A001477, the nonnegative integers.
Cf. A027480, the sequence of row sums for a regular triangle.

Programs

  • Mathematica
    Module[{s = -1},
     Table[s +=
       PartitionsP[
        n - 1]; (s + PartitionsP[n]) (s + PartitionsP[n] - 1)/2 -
       s (s - 1)/2, {n, 1, 30}]]
Showing 1-4 of 4 results.