A283893 -id:A283893 - cp's OEIS frontend

A283894 Relative of Hofstadter Q-sequence: a(1) = 17, a(2) = 2; thereafter a(n) = a(n-a(n-1)) + a(n-a(n-2)).

17, 2, 17, 2, 17, 2, 17, 2, 17, 2, 17, 2, 17, 2, 17, 2, 17, 19, 2, 36, 2, 36, 2, 36, 2, 36, 2, 36, 2, 36, 2, 36, 2, 36, 2, 36, 19, 4, 38, 38, 34, 4, 55, 38, 17, 4, 91, 38, 17, 4, 127, 38, 17, 21, 40, 4, 34, 57, 4, 21, 72, 34, 2, 70, 2, 70, 2, 70, 2, 70, 19, 19, 42, 76, 2

Offset: 1

Nathan Fox, Mar 19 2017

nonn

In calculating terms of this sequence, use the convention that a(n)=0 for n <= 0.

Most terms in this sequence alternate between 2 and a large number. Such runs of terms are separated by 102 other terms, and each run is approximately twice as long as the previous.

Nathan Fox, Table of n, a(n) for n = 1..10000

Cf. A005185, A278066, A278067, A278068, A283893, A283895, A283896, A283897.

A283894:=proc(n) option remember: if n <= 0 then 0: elif n = 1 then 17: elif n = 2 then 2: else A283894(n-A283894(n-1)) + A283894(n-A283894(n-2)): fi: end:

For nonnegative integers i, if 1 <= 2n + r <= 594*2^(i+1) - 2, then
a(594*2^i + 100 + 2n) = 2
a(594*2^i + 100 + 2n + 1) = 594*2^(i+1) - 2.

A283895 Relative of Hofstadter Q-sequence: a(1) = 41, a(2) = 2; thereafter a(n) = a(n-a(n-1)) + a(n-a(n-2)).

Original entry on oeis.org

41, 2, 41, 2, 41, 2, 41, 2, 41, 2, 41, 2, 41, 2, 41, 2, 41, 2, 41, 2, 41, 2, 41, 2, 41, 2, 41, 2, 41, 2, 41, 2, 41, 2, 41, 2, 41, 2, 41, 2, 41, 43, 2, 84, 2, 84, 2, 84, 2, 84, 2, 84, 2, 84, 2, 84, 2, 84, 2, 84, 2, 84, 2, 84, 2, 84, 2, 84, 2, 84, 2, 84, 2, 84, 2

Offset: 1

Nathan Fox, Mar 19 2017

nonn

In calculating terms of this sequence, use the convention that a(n)=0 for n<=0.

Most terms in this sequence alternate between 2 and a large constant. Such runs of terms are eventually separated by either 224 or 562 other terms, and each run is approximately twice as long as the previous.

Nathan Fox, Table of n, a(n) for n = 1..50000

Cf. A005185, A278066, A278067, A278068, A283893, A283894, A283896, A283897.

A283895:=proc(n) option remember: if n <= 0 then 0: elif n = 1 then 41: elif n = 2 then 2: else A283895(n-A283895(n-1)) + A283895(n-A283895(n-2)): fi: end:

A283896 Relative of Hofstadter Q-sequence: a(-88) = 89, a(-87) = 2; thereafter a(n) = a(n-a(n-1)) + a(n-a(n-2)).

Original entry on oeis.org

91, 2, 180, 2, 180, 2, 180, 2, 180, 2, 180, 2, 180, 2, 180, 2, 180, 2, 180, 2, 180, 2, 180, 2, 180, 2, 180, 2, 180, 2, 180, 2, 180, 2, 180, 2, 180, 2, 180, 2, 180, 2, 180, 2, 180, 2, 180, 2, 180, 2, 180, 2, 180, 2, 180, 2, 180, 2, 180, 2, 180, 2, 180, 2, 180, 2, 180, 2, 180, 2, 180, 2, 180, 2, 180

Offset: 1

Nathan Fox, Mar 19 2017

In calculating terms of this sequence, use the convention that a(n)=0 for n<=-89.
Sequences like this are more naturally considered with the first nonzero term in position 1. But this sequence would then begin with 89 terms consisting entirely of alternating 2 and 89.
This sequence has exactly 2467 terms, since a(2467)=0 and computing a(2468) would refer to itself.

Nathan Fox, Table of n, a(n) for n = 1..2467

Cf. A005185, A278066, A278067, A278068, A283893, A283894, A283895, A283897.

A283896:=proc(n) option remember: if n <= -89 then 0: elif n = -88 then 89: elif n = -87 then 2: else A283896(n-A283896(n-1)) + A283896(n-A283896(n-2)): fi: end:

A283897 Relative of Hofstadter Q-sequence: a(-90) = 91, a(-89) = 2; thereafter a(n) = a(n-a(n-1)) + a(n-a(n-2)).

Original entry on oeis.org

93, 2, 184, 2, 184, 2, 184, 2, 184, 2, 184, 2, 184, 2, 184, 2, 184, 2, 184, 2, 184, 2, 184, 2, 184, 2, 184, 2, 184, 2, 184, 2, 184, 2, 184, 2, 184, 2, 184, 2, 184, 2, 184, 2, 184, 2, 184, 2, 184, 2, 184, 2, 184, 2, 184, 2, 184, 2, 184, 2

Offset: 1

Nathan Fox, Mar 19 2017

In calculating terms of this sequence, use the convention that a(n)=0 for n<=-91.
Sequences like this are more naturally considered with the first nonzero term in position 1. But this sequence would then begin with 91 terms consisting entirely of alternating 2 and 91.
This sequence has exactly 375 terms, since a(375)=0 and computing a(376) would refer to itself.

Nathan Fox, Table of n, a(n) for n = 1..375

Cf. A005185, A278066, A278067, A278068, A283893, A283894, A283895, A283896.

A283897:=proc(n) option remember: if n <= -91 then 0: elif n = -90 then 91: elif n = -89 then 2: else A283897(n-A283897(n-1)) + A283897(n-A283897(n-2)): fi: end:

cp's OEIS Frontend

A283894 Relative of Hofstadter Q-sequence: a(1) = 17, a(2) = 2; thereafter a(n) = a(n-a(n-1)) + a(n-a(n-2)).

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A283895 Relative of Hofstadter Q-sequence: a(1) = 41, a(2) = 2; thereafter a(n) = a(n-a(n-1)) + a(n-a(n-2)).

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A283896 Relative of Hofstadter Q-sequence: a(-88) = 89, a(-87) = 2; thereafter a(n) = a(n-a(n-1)) + a(n-a(n-2)).

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Maple

A283897 Relative of Hofstadter Q-sequence: a(-90) = 91, a(-89) = 2; thereafter a(n) = a(n-a(n-1)) + a(n-a(n-2)).

Views

Author

Keywords

Comments

Links

Crossrefs

Programs

Maple