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 1-10 of 33 results. Next

A348246 Index of first occurrence of n in A307730.

Original entry on oeis.org

1, 2, 4, 8, 47, 7, 52, 27, 17, 60, 1374, 26, 1385, 59, 46, 137, 3738, 98, 3755, 204, 83, 1399, 6680, 136, 320, 1398, 176, 224, 6703, 345, 84626, 252, 1447, 3775, 375, 203, 84657, 3774, 1446, 502, 89480, 410, 89521, 1480, 319, 6733, 91832, 542, 452, 1024, 3847, 1618, 91879, 690, 1524, 501, 3846, 6732, 173092, 1074, 173151, 84695, 645, 807, 1579, 1735, 192882
Offset: 1

Views

Author

Rémy Sigrist and N. J. A. Sloane, Oct 17 2021

Keywords

Comments

a(n) is the least k such that A307730(k) = n.

Examples

			For n = 6:
- sequence A307730 starts: 1, 2, 2, 3, 3, 3, 6, 4, 4, 4, 4, 6, 6, 6, 6, 6,
- the first occurrence of 6 appears at position 7,
- so a(6) = 7.
		

Crossrefs

Programs

  • C
    See Links section.

Formula

A348409(n) - a(n) >= n - 1.

A348409 a(n) is the greatest k such that A307730(k) = n.

Original entry on oeis.org

1, 3, 6, 11, 51, 16, 58, 34, 25, 69, 1384, 45, 1397, 82, 97, 152, 3754, 115, 3773, 223, 135, 1420, 6702, 175, 344, 1445, 202, 251, 6731, 374, 84656, 283, 1479, 3808, 409, 318, 84693, 3845, 1617, 541, 89520, 451, 89563, 1523, 689, 6778, 91878, 589, 500, 1073
Offset: 1

Views

Author

Rémy Sigrist, Oct 17 2021

Keywords

Examples

			For n = 6:
- sequence A307730 starts: 1, 2, 2, 3, 3, 3, 6, 4, 4, 4, 4, 6, 6, 6, 6, 6,
- the sixth occurrence of 6 appears at position 16,
- so a(6) = 16.
		

Crossrefs

Programs

  • C
    See Links section.

Formula

a(n) - A348246(n) >= n - 1.

A348243 Successive terms in A307730 but listing just one of each run of identical terms.

Original entry on oeis.org

1, 2, 3, 6, 4, 6, 9, 12, 8, 12, 15, 5, 7, 14, 10, 14, 21, 15, 18, 21, 24, 16, 24, 27, 36, 20, 28, 32, 36, 45, 25, 30, 35, 42, 49, 56, 40, 48, 56, 63, 45, 54, 63, 72, 64, 72, 81, 90, 50, 60, 70, 80, 90, 99, 11, 13, 26, 22, 26, 39, 33, 44, 55, 65, 39, 52, 65, 78, 66, 78, 91, 77, 88, 99
Offset: 1

Views

Author

N. J. A. Sloane, Oct 16 2021

Keywords

Comments

Obviously the graph here is a compressed version of the graph of A307730.

Examples

			A307730 begins 1, 2, 2, 3, 3, 3, 6, 4, 4, 4, 4, 6, 6, 6, 6, 6, 9, 9, 9, 9, 9, 9, 9, 9, 9, 12, 8, 8, 8, ... Replacing runs of identical terms by a single number, we get 1, 2, 3, 6, 4, 6, 9, 12, 8, ...
		

Crossrefs

Programs

  • C
    See Links section.

A348245 If A307730(n) = i, then a(n) = 1 + number of copies of i that have already appeared in A307730.

Original entry on oeis.org

1, 1, 2, 1, 2, 3, 1, 1, 2, 3, 4, 2, 3, 4, 5, 6, 1, 2, 3, 4, 5, 6, 7, 8, 9, 1, 1, 2, 3, 4, 5, 6, 7, 8, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 1, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 6, 7, 1, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 1, 2, 3, 4, 5, 6, 7, 8, 9
Offset: 1

Views

Author

N. J. A. Sloane, Oct 16 2021

Keywords

Comments

From the definition of A307720 and A307730, we know that any number i must eventually appear exactly i times in A307730. So a(n) <= A307730(n).

Crossrefs

A348444 is another version.

A348449 Indices of records in A307730.

Original entry on oeis.org

1, 2, 4, 7, 17, 26, 46, 83, 136, 176, 203, 319, 452, 501, 645, 806, 942, 1023, 1373, 2142, 2352, 2473, 3013, 4392, 4812, 5273, 5881, 7820, 8360, 8953, 9373, 11998, 12646, 13371, 13875, 15944, 17294, 18152, 20084, 24447, 25143, 26521, 27564, 29090, 33764, 40156, 41482, 42826, 44217, 46647, 51069
Offset: 1

Views

Author

N. J. A. Sloane, Oct 23 2021

Keywords

Programs

  • C
    // See Links section.

A348247 Where prime(n) first appears in A307730.

Original entry on oeis.org

2, 4, 47, 52, 1374, 1385, 3738, 3755, 6680, 6703, 84626, 84657, 89480, 89521, 91832, 91879, 173092, 173151, 192882, 192949, 524587, 524660, 865301, 865384, 876543, 876640, 890479, 890582, 904273, 904382, 918859, 918986, 1628979, 1629116, 1647107, 1647256, 1666775
Offset: 1

Views

Author

N. J. A. Sloane, Oct 17 2021

Keywords

Crossrefs

Programs

  • Python
    from collections import Counter
    from sympy import prime
    def A348247(n):
        c, b, p, i = Counter(), 1, prime(n), 1
        while True:
            k, kb = 1, b
            while c[kb] >= kb:
                k += 1
                kb += b
            if kb == p:
                return i
            c[kb] += 1
            b = k
            i += 1 # Chai Wah Wu, Oct 21 2021

Extensions

More terms from Chai Wah Wu, Oct 21 2021

A348251 Numbers that take more than the minimum number of steps to appear in A307730.

Original entry on oeis.org

6, 12, 14, 15, 21, 24, 26, 36, 38, 39, 45, 56, 57, 58, 63, 65, 72, 74, 78, 85, 86, 87, 90, 91, 99, 106, 110, 111, 115, 119, 122, 126, 129, 132, 135, 138, 142, 143, 145, 150, 158, 159, 161, 165, 171, 174, 175, 176, 178, 183, 185, 187, 190, 202, 203, 209, 213, 214, 215, 216, 220, 222, 226, 230, 231
Offset: 1

Views

Author

N. J. A. Sloane, Oct 21 2021

Keywords

Comments

The total number of appearances of a number n in A307730 is required to be n. For the numbers listed here, those appearances are spread out over more than n terms of A307730.
These are the numbers n for which A348250(n) is nonzero.
It would be nice to have an independent characterization of these numbers. It is a theorem that no primes can appear, but what more can be said? The graph is roughly linear, and the first differences are small but irregular.

Crossrefs

A348448 Records in A307730.

Original entry on oeis.org

1, 2, 3, 6, 9, 12, 15, 21, 24, 27, 36, 45, 49, 56, 63, 72, 81, 90, 99, 110, 121, 132, 143, 150, 165, 176, 187, 190, 209, 220, 231, 243, 253, 264, 275, 290, 319, 324, 351, 360, 375, 377, 406, 435, 459, 475, 476, 493, 522, 551, 567, 575, 588, 609, 638, 667, 675, 700, 725, 754, 783, 810, 837, 858
Offset: 1

Views

Author

N. J. A. Sloane, Oct 23 2021

Keywords

Comments

The points with coordinates (x,y) = (A348449(n), A348448(n)), n = 1,2,3,... are the upper envelope of the graph of A307730. Based on the first 10^6 terms of A307730 we get 110 points on the upper envelope, which appear to lie very roughly on the curve y = x^0.57. It would be nice to have a more trustworthy expression for this curve!

Crossrefs

Programs

  • C
    // See Links section.

A348579 Triangle T(n, k), n > 0, 0 < k <= n, read by rows; the n-th row contains, in ascending order, the numbers m such that A307730(m) = n.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 8, 9, 10, 11, 47, 48, 49, 50, 51, 7, 12, 13, 14, 15, 16, 52, 53, 54, 55, 56, 57, 58, 27, 28, 29, 30, 31, 32, 33, 34, 17, 18, 19, 20, 21, 22, 23, 24, 25, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 1374, 1375, 1376, 1377, 1378, 1379, 1380, 1381, 1382, 1383, 1384
Offset: 1

Views

Author

Rémy Sigrist and N. J. A. Sloane, Oct 24 2021

Keywords

Examples

			Triangle T(n, k) begins:
  n\k|   1   2   3   4   5   6   7   8   9  10
  ---+----------------------------------------
    1|   1
    2|   2   3
    3|   4   5   6
    4|   8   9  10  11
    5|  47  48  49  50  51
    6|   7  12  13  14  15  16
    7|  52  53  54  55  56  57  58
    8|  27  28  29  30  31  32  33  34
    9|  17  18  19  20  21  22  23  24  25
   10|  60  61  62  63  64  65  66  67  68  69
		

Crossrefs

Programs

  • PARI
    See Links section.

Formula

T(n, 1) = A348246(n).
T(n, n) = A348409(n).

A348395 Terms in A307730 in order of appearance.

Original entry on oeis.org

1, 2, 3, 6, 4, 9, 12, 8, 15, 5, 7, 14, 10, 21, 18, 24, 16, 27, 36, 20, 28, 32, 45, 25, 30, 35, 42, 49, 56, 40, 48, 63, 54, 72, 64, 81, 90, 50, 60, 70, 80, 99, 11, 13, 26, 22, 39, 33, 44, 55, 65, 52, 78, 66, 91, 77, 88, 110, 100, 121, 132, 84, 96, 108, 120, 143
Offset: 1

Views

Author

Rémy Sigrist, Oct 17 2021

Keywords

Comments

Equivalently, terms in A348243 in order of appearance.

Examples

			Sequence A307730 starts: 1, 2, 2, 3, 3, 3, 6, 4, 4, 4, 4, 6, 6, 6, 6, 6, 9.
So the present sequence starts: 1, 2, 3, 6, 4, 9.
		

Crossrefs

Programs

  • C
    See Links section.
Showing 1-10 of 33 results. Next