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.

A348356 Square array T(n, k), n, k > 0, read by antidiagonal upwards; the k-th column contains, in ascending order, the integers m such that A348330(m) = k.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 8, 9, 7, 10, 16, 18, 14, 11, 12, 32, 36, 28, 22, 13, 15, 64, 72, 56, 44, 26, 17, 19, 128, 144, 112, 88, 52, 33, 20, 21, 256, 288, 224, 176, 104, 66, 40, 23, 24, 512, 576, 448, 352, 208, 132, 80, 45, 25, 27, 1024, 1152, 896, 704, 416, 264, 160, 90, 50, 29, 30, 2048, 2304, 1792, 1408, 832, 528, 320, 180, 100, 57, 31, 34
Offset: 1

Views

Author

Rémy Sigrist, Oct 14 2021

Keywords

Comments

When interpreted as a flat array, we have a permutation of the positive integers.

Examples

			Array T(n, k) begins:
  n\k|    1     2     3     4     5     6     7     8     9    10
  ---+-----------------------------------------------------------
    1|    1     3     6    10    12    15    19    21    24    27
    2|    2     5     7    11    13    17    20    23    25    29
    3|    4     9    14    22    26    33    40    45    50    57
    4|    8    18    28    44    52    66    80    90   100   114
    5|   16    36    56    88   104   132   160   180   200   228
    6|   32    72   112   176   208   264   320   360   400   456
    7|   64   144   224   352   416   528   640   720   800   912
    8|  128   288   448   704   832  1056  1280  1440  1600  1824
    9|  256   576   896  1408  1664  2112  2560  2880  3200  3648
   10|  512  1152  1792  2816  3328  4224  5120  5760  6400  7296
		

Crossrefs

Programs

  • PARI
    See Links section.

Formula

Sum_{i = 1..n-1} T(i, k) < T(n, k).
T(n, 1) = 2^(n-1).

A348330 Lexicographically earliest sequence of positive integers such that for any n > 0, the sum of the indices k < n such that a(k) = a(n) is strictly less than n.

Original entry on oeis.org

1, 1, 2, 1, 2, 3, 3, 1, 2, 4, 4, 5, 5, 3, 6, 1, 6, 2, 7, 7, 8, 4, 8, 9, 9, 5, 10, 3, 10, 11, 11, 1, 6, 12, 12, 2, 13, 13, 14, 7, 14, 15, 15, 4, 8, 16, 16, 17, 17, 9, 18, 5, 18, 19, 19, 3, 10, 20, 20, 21, 21, 11, 22, 1, 22, 6, 23, 23, 24, 12, 24, 2, 25, 25, 26
Offset: 1

Views

Author

Rémy Sigrist, Oct 13 2021

Keywords

Comments

Every integer appears infinitely many times.
See table A348356 where the integers are arranged according to the present sequence.

Crossrefs

Programs

  • PARI
    s=vector(25); for (n=1, 75, for (k=1, oo, if (s[k]
    				

Formula

a(n) = 1 iff n is a power of 2 (A000079).

A348331 Lexicographically earliest sequence of positive integers such that for any n > 0, the sum of the indices k < n such that a(k) = a(n) is less than or equal to n.

Original entry on oeis.org

1, 1, 1, 2, 2, 1, 3, 3, 2, 4, 4, 1, 5, 5, 3, 6, 6, 2, 7, 7, 4, 8, 8, 1, 9, 9, 5, 10, 10, 3, 11, 11, 6, 12, 12, 2, 13, 13, 7, 14, 14, 4, 15, 15, 8, 16, 16, 1, 17, 17, 9, 18, 18, 5, 19, 19, 10, 20, 20, 3, 21, 21, 11, 22, 22, 6, 23, 23, 12, 24, 24, 2, 25, 25, 13
Offset: 1

Views

Author

Rémy Sigrist, Oct 13 2021

Keywords

Comments

Every integer appears infinitely many times.
See table A348357 where the integers are arranged according to the present sequence.

Crossrefs

Programs

  • PARI
    s=vector(25); for (n=1, 75, for (k=1, oo, if (s[k]<=n, print1 (k", "); s[k]+=n; break)))

Formula

a(n) = 1 iff n belongs to A098011.
Showing 1-3 of 3 results.