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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A283887 Relative of Hofstadter Q-sequence: a(n) = max(0, n+20830) for n <= 0; a(n) = a(n-a(n-1)) + a(n-a(n-2)) + a(n-a(n-3)) for n > 0.

Original entry on oeis.org

6, 20831, 20832, 20833, 9, 20834, 20835, 20836, 12, 20837, 20838, 20839, 15, 20840, 20841, 17, 20843, 18, 20843, 20845, 20846, 22, 21, 41671, 41665, 9, 18, 41680, 41683, 20839, 22, 20860, 20865, 20843, 27, 36, 20867, 41670, 20834, 39
Offset: 1

Views

Author

Nathan Fox, Mar 19 2017

Keywords

Comments

Sequences like this are more naturally considered with the first nonzero term in position 1. But this sequence would then match A000027 for its first 20830 terms.
Most terms in this sequence appear in one of two long patterns of 16 interleaved sequences. The first stretches from a(64180) through a(9029945). The second stretches from a(9029971) through a(-20830 + 84975*2^560362).
This sequence has exactly -20799 + 84975*2^560362 terms (of positive index). a(-20799 + 84975*2^560362) = 0, so an attempt to calculate a(-20798 + 84975*2^560362) would refer to itself.

Crossrefs

Programs

Formula

If the index is between 67 and 20831 (inclusive), then a(7n) = 7n+2, a(7n+1) = 7n+20832, a(7n+2) = 7n+20834, a(7n+3) = 7, a(7n+4) = 2n+41705, a(7n+5) = n+41653, a(7n+6) = 20828.

A283888 Relative of Hofstadter Q-sequence: a(n) = max(0, n+27298) for n <= 0; a(n) = a(n-a(n-1)) + a(n-a(n-2)) + a(n-a(n-3)) for n > 0.

Original entry on oeis.org

6, 27299, 27300, 27301, 9, 27302, 27303, 27304, 12, 27305, 27306, 27307, 15, 27308, 27309, 17, 27311, 18, 27311, 27313, 27314, 22, 21, 54607, 54601, 9, 18, 54616, 54619, 27307, 22, 27328, 27333, 27311, 27, 36, 27335, 54606, 27302, 39
Offset: 1

Views

Author

Nathan Fox, Mar 19 2017

Keywords

Comments

Sequences like this are more naturally considered with the first nonzero term in position 1. But this sequence would then match A000027 for its first 27298 terms.
Most terms in this sequence appear in a long pattern stretching from a(85652) through a(141867984), of 16 interleaved sequences.
This sequence has exactly 141868181 terms (of positive index). a(141868181) = 0, so an attempt to calculate a(141868182) would refer to itself.

Crossrefs

Programs

Formula

If the index is between 67 and 27299 (inclusive), then a(7n) = 7n+2, a(7n+1) = 7n+27300, a(7n+2) = 7n+27302, a(7n+3) = 7, a(7n+4) = 2n+54641, a(7n+5) = n+54589, a(7n+6) = 27296.

A283883 Relative of Hofstadter Q-sequence: a(n) = max(0, n+117) for n <= 0; a(n) = a(n-a(n-1)) + a(n-a(n-2)) for n > 0.

Original entry on oeis.org

3, 118, 119, 5, 120, 6, 7, 121, 123, 10, 8, 123, 127, 12, 124, 14, 129, 11, 128, 132, 16, 13, 17, 15, 131, 20, 20, 242, 123, 24, 32, 238, 3, 32, 357, 5, 238, 3, 5, 595, 5, 238, 3, 5, 833, 5, 238, 3, 5, 1071, 5, 238, 3, 5, 1309, 5, 238, 3, 5, 1547, 5, 238, 3, 5, 1785, 5, 238, 3, 5, 2023, 5, 238, 3, 5, 2261
Offset: 1

Views

Author

Nathan Fox, Mar 19 2017

Keywords

Comments

Sequences like this are more naturally considered with the first nonzero term in position 1. But this sequence would then match A000027 for its first 117 terms.
This sequence has exactly 3346939303954 terms (of positive index). a(3346939303954) = 0, so an attempt to calculate a(3346939303955) would refer to itself.

Crossrefs

Programs

Formula

If the index is between 35 and 122 (inclusive), then a(5n) = 238n-1309, a(5n+1) = 5, a(5n+2) = 238, a(5n+3) = 3, a(5n+4) = 5.
If the index is between 128 and 4525 (inclusive), then a(5n) = 4641, a(5n+1) = 3, a(5n+2) = 5, a(5n+3) = 4641n-106981, a(5n+4) = 5.
If the index is between 4531 and 4093008 (inclusive), then a(5n) = 5, a(5n+1) = 4093124n-3700188737, a(5n+2) = 5, a(5n+3) = 4093124, a(5n+4) = 3.
If the index is between 4093008 and 3346939303796 (inclusive), then a(5n) = 5, a(5n+1) = 3346939303911, a(5n+2) = 3, a(5n+3) = 5, a(5n+4) = 3346939303911n-2739804514185637724.

A283882 Relative of Hofstadter Q-sequence: a(n) = max(0, n+67) for n <= 0; a(n) = a(n-a(n-1)) + a(n-a(n-2)) for n > 0.

Original entry on oeis.org

3, 68, 69, 5, 70, 6, 7, 71, 73, 10, 8, 73, 77, 12, 74, 14, 79, 11, 78, 82, 16, 13, 17, 15, 81, 20, 20, 142, 73, 24, 32, 138, 3, 32, 207, 5, 138, 3, 5, 345, 5, 138, 3, 5, 483, 5, 138, 3, 5, 621, 5, 138, 3, 5, 759, 5, 138, 3, 5, 897, 5, 138, 3, 5, 1035, 5, 138, 3, 5, 1173, 5, 138, 5, 8, 1311
Offset: 1

Views

Author

Nathan Fox, Mar 19 2017

Keywords

Comments

Sequences like this are more naturally considered with the first nonzero term in position 1. But this sequence would then match A000027 for its first 67 terms.

Crossrefs

Programs

Formula

If the index is between 35 and 72 (inclusive), then a(5n) = 138n-759, a(5n+1) = 5, a(5n+2) = 138, a(5n+3) = 3, a(5n+4) = 5.
If the index is between 78 and 1245 (inclusive), then a(5n) = 1311, a(5n+1) = 3, a(5n+2) = 5, a(5n+3) = 1311n-17181, a(5n+4) = 5.
If the index is between 1251 and 309192 (inclusive), then a(5n) = 5, a(5n+1) = 19047817435n-1178393232110703, a(5n+2) = 5, a(5n+3) = 19047817435, a(5n+4) = 3.
If the index is between 309336 and 19047817368 (inclusive), then a(5n) = 5, a(5n+1) = 309258n-76697295, a(5n+2) = 5, a(5n+3) = 309258, a(5n+4) = 3.
If the index is at least 19047817371, then a(5n) = 5*A272611(n-3809563474), a(5n+1) = 5*A272611(n-3809563473), a(5n+2) = 5*A272612(n-3809563473), a(5n+3) = 19047817435*A272613(n-3809563473), a(5n+4) = 4. This pattern lasts as long as A272611 exists (which is conjectured to be forever).
Previous Showing 11-14 of 14 results.