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.

A230565 a(n)*|a(n)| gives the first difference of A230455.

Original entry on oeis.org

1, 2, 3, 4, 5, -7, 6, 8, -9, 10, -11, 12, 13, -17, 14, 15, -21, 16, 18, -24, 19, 20, -27, 22, 23, -32, 25, 26, -36, 28, 29, -40, 30, -31, 33, 34, -46, 35, 37, -52, 38, 39, -54, 41, 42, -59, 43, 44, -61, 45, 47, -65, 48, -49, 50, 51, -70, 53, 55, -77, 56, -57
Offset: 1

Views

Author

Paul Tek, Oct 23 2013

Keywords

Comments

This sequence contains only terms with distinct absolute values, different from 0.

Links

Crossrefs

Cf. A230455, A230560.

A230383 Lexicographically earliest sequence of distinct positive integers such that the first difference contains only distinct positive or negative squares.

Original entry on oeis.org

1, 2, 6, 5, 14, 10, 26, 17, 42, 78, 29, 4, 53, 37, 101, 20, 120, 56, 137, 16, 160, 60, 24, 145, 314, 25, 221, 52, 277, 21, 310, 85, 341, 197, 521, 80, 441, 41, 482, 121, 605, 76, 476, 152, 681, 105, 730, 54, 630, 146, 822, 38, 767, 142, 926, 1767, 3, 903, 62
Offset: 1

Views

Author

Paul Tek, Oct 17 2013

Keywords

Comments

Is this a permutation of the positive integers ?
Will every square show up in the first difference ?

Examples

			n  a(n)   First difference
-  ----   ----------------
1     1
          +1^2
2     2
          +2^2
3     6
          -1^2
4     5
          +3^2
5    14
          -2^2
6    10
          +4^2
7    26
          ...

Links

Crossrefs

Cf. A081145, A175498, A230455, A230560.

Programs

  • Perl
    See Link section.

A293666 Lexicographically earliest sequence of distinct positive integers such that the absolute value of the first difference contains only distinct prime numbers.

Original entry on oeis.org

1, 3, 6, 11, 4, 15, 2, 19, 38, 7, 30, 59, 12, 49, 8, 51, 104, 21, 80, 9, 70, 137, 10, 83, 162, 5, 94, 191, 18, 119, 16, 123, 14, 127, 258, 17, 154, 293, 22, 171, 20, 183, 350, 13, 192, 373, 24, 215, 408, 25, 222, 23, 234, 457, 26, 253, 482, 33, 266, 27, 278
Offset: 1

Views

Author

Rémy Sigrist, Oct 14 2017

Keywords

Comments

This sequence is a variant of A081145 and of A230455.
See A293667 for the first difference of this sequence.
For n > 1, n is even iff a(n) is odd.

Examples

			The following table shows the first terms, alongside the first terms of the first difference:
n       a(n)    a(n+1)-a(n)
--      ----    -----------
1       1       2
2       3       3
3       6       5
4       11      -7
5       4       11
6       15      -13
7       2       17
8       19      19
9       38      -31
10      7       23
11      30      29
12      59      -47
13      12      37
14      49      -41
15      8       43
16      51      53
17      104     -83
18      21      59
19      80      -71
20      9       61

Links

Crossrefs

Cf. A081145, A230455, A293667.

Programs

  • PARI
    See Links section.
Showing 1-3 of 3 results.

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

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