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.

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A337276 Index of appearance of 2*n in A336957, or -1 if 2*n never appears.

Original entry on oeis.org

2, -1, 3, -1, 10, 7, 6, -1, 11, 15, 14, 35, 18, 19, 31, -1, 22, 39, 23, 27, 30, 43, 26, 67, 42, 47, 71, 34, 51, 63, 46, -1, 75, 55, 50, 79, 54, 38, 83, 59, 58, 62, 87, 91, 90, 95, 99, 94, 66, 70, 86, 103, 106, 98, 74, 82, 119, 102, 107, 123, 110, 111, 118, -1, 115, 127, 114, 122, 146, 131, 134
Offset: 1

Views

Author

N. J. A. Sloane, Sep 09 2020

Keywords

Comments

It is a strong conjecture that 2*n appears in A336957 for all odd n, and it is known that 2^i does not appear for i>1.

Examples

			A336957(14) = 22, so a(11) = 14.

Crossrefs

Cf. A336957, A337275.

A337280 Index of first term in A336957 that is divisible by the n-th prime.

Original entry on oeis.org

2, 3, 4, 5, 8, 17, 21, 23, 25, 40, 45, 53, 57, 68, 72, 105, 107, 109, 113, 133, 135, 141, 155, 171, 181, 188, 192, 204, 209, 213, 255, 259, 271, 273, 295, 299, 315, 323, 325, 340, 352, 356, 389, 391, 393, 397, 412, 451, 471, 475, 477, 491, 495, 511, 523, 531, 543, 547, 567, 575, 579, 599, 627, 639, 643, 647, 675, 691, 715
Offset: 1

Views

Author

N. J. A. Sloane, Sep 12 2020

Keywords

Examples

			A336957(8) = 33 is the first term in A336957 that is divisible by prime(5) = 11, so a(5) = 8.

Links

Crossrefs

Cf. A336957.

Programs

  • C
    See Links section.

A337649 Primes p such that the first term in {A336957(i): i >= 3} that is divisible by p is 3*p.

Original entry on oeis.org

2, 5, 11, 13, 17, 23, 29, 31, 37, 41, 43, 47, 53, 61, 67, 71, 79, 97, 101, 103, 107, 109, 113, 139, 167, 173, 179, 181, 191, 197, 199, 211, 233, 367
Offset: 1

Views

Author

N. J. A. Sloane, Sep 26 2020

Keywords

Comments

It is conjectured that there are no other terms besides the 34 terms shown here.
See A337648 for further comments.
See also the comment in A336957 discussing when primes first appear in A336957.

Examples

			2 is a term because the first even term in {A336957(i): i >= 3} is A336957(3) = 6 = 3*2.

Crossrefs

Cf. A336957, A337648.

A338056 Values of k where A336957(k)/k sets a new record.

Original entry on oeis.org

1, 3, 4, 5, 182735, 243638, 456498, 578004, 669156, 1063563, 1093967, 1671118, 1974220, 2125785, 2398346, 2428677, 3428717, 3732005, 4065453, 4458923, 4640700, 8760267
Offset: 1

Views

Author

Scott R. Shannon and N. J. A. Sloane, Oct 12 2020

Keywords

Comments

The factorizations of the a(n) values (which are in A338057) are
1, (2) (3), (3) (5), (5) (7), (17) (90089), (17) (120121),
(17) (225217), (17) (285287), (17) (330313), (17) (525529),
(17) (540557), (17) (825821), (17) (975977), (17) (1051051),
(17) (1186181), (17) (1201201), (17) (1696697), (17) (1846843),
(17) (2012009), (17) (2207213), (19) (2297297), (19) (4339343),
which suggests that both the current sequence and A338057 are infinite.

Examples

			Table showing records for A336957(k)/k:
     k   A336957(k)    A336957(k)/k
     1           1     1
     3           6     2
     4          15     3.75
     5          35     7
182735     1531513     8.38106
243638     2042057     8.38152
456498     3828689     8.38709
578004     4849879     8.39074
669156     5615321     8.39165
1063563     8933993     8.40006
1093967     9189469     8.40013
1671118     14038957     8.40094
1974220     16591609     8.40413
2125785     17867867     8.4053
2398346     20165077     8.40791
2428677     20420417     8.40804
3428717     28843849     8.41243
3732005     31396331     8.41272
4065453     34204153     8.41337
4458923     37522621     8.41518
4640700     43648643     9.40562
8760267     82447517     9.41153

Crossrefs

Cf. A336957, A338057.

A338063 Odd terms in A336957 in order of appearance.

Original entry on oeis.org

1, 15, 35, 33, 55, 21, 77, 45, 39, 63, 51, 57, 69, 65, 91, 85, 119, 75, 95, 87, 145, 99, 93, 117, 105, 261, 111, 153, 123, 115, 161, 155, 217, 129, 215, 141, 235, 147, 133, 135, 175, 143, 187, 301, 189, 209, 171, 253, 165, 329, 203, 195, 159, 177, 183, 279, 201, 185, 259, 247, 221, 205
Offset: 1

Views

Author

N. J. A. Sloane, Oct 18 2020

Keywords

Links

Crossrefs

Cf. A336957, A338062-A338069.

A338068 Numbers k such that A336957(k) is even and less than k.

Original entry on oeis.org

31, 35, 39, 63, 67, 71, 75, 79, 83, 87, 91, 95, 99, 119, 123, 146, 158, 187, 198, 215, 218, 223, 227, 231, 234, 239, 255, 279, 283, 307, 311, 315, 331, 335, 339, 343, 346, 347, 351, 354, 355, 359, 363, 367, 370, 371, 375, 378, 379, 383, 387, 390, 391, 395, 402, 403, 407, 411, 415, 418
Offset: 1

Views

Author

N. J. A. Sloane, Oct 19 2020

Keywords

Links

Crossrefs

Cf. A336957, A338062-A338069.

A338064 Numbers k such that the Enots Wolley sequence A336957(k) is even.

Original entry on oeis.org

2, 3, 6, 7, 10, 11, 14, 15, 18, 19, 22, 23, 26, 27, 30, 31, 34, 35, 38, 39, 42, 43, 46, 47, 50, 51, 54, 55, 58, 59, 62, 63, 66, 67, 70, 71, 74, 75, 78, 79, 82, 83, 86, 87, 90, 91, 94, 95, 98, 99, 102, 103, 106, 107, 110, 111, 114, 115, 118, 119, 122, 123, 126, 127, 130, 131, 134
Offset: 1

Views

Author

N. J. A. Sloane, Oct 18 2020

Keywords

Comments

a(n) = A053438(n) for 1 <= n < 1065, but then the two sequences start to differ. - R. J. Mathar, Oct 26 2020

Links

Crossrefs

Cf. A336957, A338062-A338069.

A338065 Even terms in A336957, divided by 2, in order of appearance.

Original entry on oeis.org

1, 3, 7, 6, 5, 9, 11, 10, 13, 14, 17, 19, 23, 20, 21, 15, 28, 12, 38, 18, 25, 22, 31, 26, 35, 29, 37, 34, 41, 40, 42, 30, 49, 24, 50, 27, 55, 33, 76, 36, 56, 39, 51, 43, 45, 44, 48, 46, 54, 47, 58, 52, 53, 59, 61, 62, 67, 65, 63, 57, 68, 60, 77, 66, 91, 70, 71, 73, 88, 74, 79, 80, 69, 82
Offset: 1

Views

Author

N. J. A. Sloane, Oct 18 2020

Keywords

Links

Crossrefs

Cf. A336957, A338062-A338069.

A338066 Numbers k such that A336957(k) is even and greater than k.

Original entry on oeis.org

3, 6, 7, 11, 14, 15, 18, 19, 22, 23, 26, 27, 30, 34, 38, 42, 43, 46, 47, 50, 51, 54, 55, 58, 59, 62, 66, 70, 74, 78, 82, 86, 94, 98, 102, 103, 107, 110, 111, 114, 115, 118, 122, 126, 127, 130, 131, 134, 135, 138, 139, 142, 143, 147, 151, 154, 155, 159, 163, 166, 167, 170, 171, 174, 175
Offset: 1

Views

Author

N. J. A. Sloane, Oct 18 2020

Keywords

Links

Crossrefs

Cf. A336957, A338062-A338069.

A338067 Even terms A336957(k) which are greater than k, divided by 2, in order of appearance.

Original entry on oeis.org

3, 7, 6, 9, 11, 10, 13, 14, 17, 19, 23, 20, 21, 28, 38, 25, 22, 31, 26, 35, 29, 37, 34, 41, 40, 42, 49, 50, 55, 76, 56, 51, 48, 54, 58, 52, 59, 61, 62, 67, 65, 63, 68, 77, 66, 91, 70, 71, 73, 88, 74, 79, 80, 82, 78, 99, 83, 86, 85, 84, 87, 95, 89, 166, 92, 133, 94, 97, 98, 118, 100
Offset: 1

Views

Author

N. J. A. Sloane, Oct 18 2020

Keywords

Links

Crossrefs

Cf. A336957, A338062-A338069.
Previous Showing 21-30 of 127 results. Next

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

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