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 1-4 of 4 results.

A081827 Successive differences of Hofstadter Q-sequence.

Original entry on oeis.org

0, 1, 1, 0, 1, 1, 0, 1, 0, 0, 2, 0, 0, 2, -1, 1, 1, 0, 1, 0, 0, 0, 4, -2, 0, 2, 0, 0, 0, 4, -3, 0, 3, 1, -2, 1, 2, -1, 1, 1, 0, 1, 0, 0, 0, 0, 8, -8, 1, 5, -2, -2, 4, 0, -2, 4, -2, 2, 0, 0, 0, 8, -7, -2, 7, -3, -2, 6, 1, -3, 1, 2, -1, 1, -1, 3, -2, 1, 2, 1, -1, 0, 3, -2, 1, 2, 0, -1, 2, 0, 0, 0, 0, 0, 16, -23, 11, 2, 2
Offset: 1

Views

Author

Benoit Cloitre, Apr 10 2003

Keywords

Comments

a(A081829(n))<0; a(A081828(n))=0; a(A081830(n))>0; a(A194626(n))=1. [Reinhard Zumkeller, Sep 15 2011]

Links

Programs

  • Haskell
    a081827 n = a081827_list !! (n-1)
a081827_list = zipWith (-) (tail a005185_list) a005185_list
b081827 = bFile "A081827" a081827_list 1 10000 -- (0.34 secs)
-- Reinhard Zumkeller, Sep 15 2011

Formula

a(n)=A005185(n+1)-A005185(n).

A081828 Numbers n such that 2 successive terms of Hofstadter Q-sequence are the same.

Original entry on oeis.org

1, 4, 7, 9, 10, 12, 13, 18, 20, 21, 22, 25, 27, 28, 29, 32, 41, 43, 44, 45, 46, 54, 59, 60, 61, 82, 87, 90, 91, 92, 93, 94, 102, 111, 133, 154, 157, 163, 177, 182, 186, 187, 188, 189, 190, 273, 334, 342, 350, 360, 367, 378, 379, 380, 381, 382, 418, 431, 441, 464, 483
Offset: 1

Views

Author

Benoit Cloitre, Apr 10 2003

Keywords

Comments

A005185(a(n)+1) = A005185(a(n)); A081827(a(n)) = 0.

Links

Crossrefs

Cf. A081829, A081830, A194626.

Programs

  • Haskell
    import Data.List (elemIndices)
a081828 n = a081828_list !! (n-1)
a081828_list = map (+ 1) $ elemIndices 0 a081827_list
-- Reinhard Zumkeller, Sep 15 2011

A081829 Numbers n such that the n-th term of Hofstadter Q-sequence is > (n+1)-th term.

Original entry on oeis.org

15, 24, 31, 35, 38, 48, 51, 52, 55, 57, 63, 64, 66, 67, 70, 73, 75, 77, 81, 84, 88, 96, 100, 103, 105, 109, 112, 115, 118, 119, 121, 124, 126, 127, 128, 130, 135, 138, 140, 141, 143, 144, 147, 149, 150, 152, 155, 158, 160, 162, 165, 168, 169, 171, 172, 174, 179
Offset: 1

Views

Author

Benoit Cloitre, Apr 10 2003

Keywords

Comments

A005185(a(n)+1) < A005185(a(n)); A081827(a(n)) < 0.

Links

Crossrefs

Cf. A081828, A081830, A194626.

Programs

  • Haskell
    import Data.List (findIndices)
a08182 n = a081829_list !! (n-1)
a081829_list = map (+ 1) $ findIndices (< 0) a081827_list
-- Reinhard Zumkeller, Sep 15 2011

Formula

Conjecture : a(n)/n>2 and a(n)/n->2

A194626 Numbers n such that next term of Hofstadter's Q-sequence differs by 1.

Original entry on oeis.org

2, 3, 5, 6, 8, 16, 17, 19, 34, 36, 39, 40, 42, 49, 69, 71, 74, 78, 80, 85, 132, 167, 175, 176, 180, 181, 225, 238, 261, 271, 320, 331, 338, 340, 341, 353, 365, 371, 507, 689, 690, 706, 721, 738, 746, 921, 932, 952, 990, 1012, 1046, 1212, 1351, 1352, 1373
Offset: 1

Views

Author

Reinhard Zumkeller, Sep 15 2011

Keywords

Comments

A005185(a(n)+1) = A005185(a(n)) + 1; A081827(a(n)) = 1.

Links

Crossrefs

Cf. A081828, A081829, A081830.

Programs

  • Haskell
    import Data.List (elemIndices)
a194626 n = a194626_list !! (n-1)
a194626_list = map (+ 1) $ elemIndices 1 a081827_list
Showing 1-4 of 4 results.

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

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