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 1-5 of 5 results.

A072784 Differences between A072741 and A072737.

Original entry on oeis.org

0, 0, -1, 0, 1, -1, 0, 0, 1, -1, 0, 0, 0, 1, -1, 0, 0, 0, -1, 1, -1, 0, 0, 0, 1, -1, 1, -1, 0, 0, 0, 0, 1, -1, 1, -1, 0, 0, 0, 0, 0, 1, -1, 1, -1, 0, 0, 0, 0, 0, -1, 1, -1, 1, -1, 0, 0, 0, 0, 0, 1, -1, 1, -1, 1, -1, 0, 0, 0, 0, 0, 0, 1, -1, 1, -1, 1, -1, 0, 0, 0, 0, 0, 0, 0, 1, -1, 1, -1, 1, -1, 0, 0, 0, 0, 0, 0, 0, -1, 1, -1, 1, -1, 1, -1, 0, 0, 0, 0, 0, 0, 0, 1
Offset: 0

Views

Author

Antti Karttunen, Jun 12 2002

Keywords

Programs

A072734 Simple triangle-stretching N X N -> N bijection, variant of A072732.

Original entry on oeis.org

0, 1, 2, 3, 12, 4, 7, 17, 18, 5, 6, 23, 40, 24, 8, 11, 31, 49, 50, 25, 9, 10, 30, 59, 84, 60, 32, 13, 16, 39, 71, 97, 98, 61, 33, 14, 15, 38, 70, 111, 144, 112, 72, 41, 19, 22, 48, 83, 127, 161, 162, 113, 73, 42, 20, 21, 47, 82, 126, 179, 220, 180, 128, 85, 51, 26, 29, 58
Offset: 0

Views

Author

Antti Karttunen, Jun 12 2002

Keywords

Crossrefs

Inverse: A072735, projections: A072740 & A072741, variant of the same theme: A072732. Used to construct the global arithmetic ranking scheme of plane binary trees presented in A072787/A072788. Cf. also A001477 and its projections A025581 & A002262.

Programs

  • Scheme
    (define (A072734 n) (packA072734 (A025581 n) (A002262 n)))
    (define (packA001477 x y) (/ (+ (expt (+ x y) 2) x (* 3 y)) 2))
    (define (packA072734 x y) (let ((x-y (- x y))) (cond ((negative? x-y) (packA001477 (+ (* 2 x) (modulo (1+ x-y) 2)) (+ (* 2 x) (floor->exact (/ (+ (- x-y) (modulo x-y 2)) 2))))) ((< x-y 3) (packA001477 (+ (* 2 y) x-y) (* 2 y))) (else (packA001477 (+ (* 2 y) (floor->exact (/ (1+ x-y) 2)) (modulo (1+ x-y) 2)) (+ (* 2 y) (modulo x-y 2)))))))

A072740 X-projection of the tabular N X N -> N bijection A072734.

Original entry on oeis.org

0, 1, 0, 2, 0, 0, 4, 3, 0, 0, 6, 5, 1, 0, 0, 8, 7, 2, 1, 0, 0, 10, 9, 3, 1, 1, 0, 0, 12, 11, 5, 4, 1, 1, 0, 0, 14, 13, 7, 6, 2, 1, 1, 0, 0, 16, 15, 9, 8, 3, 2, 1, 1, 0, 0, 18, 17, 11, 10, 4, 2, 2, 1, 1, 0, 0, 20, 19, 13, 12, 6, 5, 2, 2, 1, 1, 0, 0, 22, 21, 15, 14, 8, 7, 3, 2, 2, 1, 1, 0, 0, 24, 23
Offset: 0

Views

Author

Antti Karttunen, Jun 12 2002

Keywords

Crossrefs

The Y-projection is A072741. Composition of A025581 and A072735. A072783(n) = A072740(n)-A072736(n).

Programs

A072737 Y-projection of the tabular N X N -> N bijection A072732.

Original entry on oeis.org

0, 0, 2, 0, 1, 4, 0, 0, 3, 6, 0, 0, 1, 5, 8, 0, 0, 1, 3, 7, 10, 0, 0, 1, 2, 5, 9, 12, 0, 0, 1, 1, 4, 7, 11, 14, 0, 0, 1, 1, 2, 6, 9, 13, 16, 0, 0, 1, 1, 2, 4, 8, 11, 15, 18, 0, 0, 1, 1, 2, 3, 6, 10, 13, 17, 20, 0, 0, 1, 1, 2, 2, 5, 8, 12, 15, 19, 22, 0, 0, 1, 1, 2, 2, 3, 7, 10, 14, 17, 21, 24, 0, 0
Offset: 0

Views

Author

Antti Karttunen, Jun 12 2002

Keywords

Crossrefs

The X-projection is A072736. Composition of A002262 and A072733. A072784(n) = A072741(n)-A072737(n).

Programs

A072788 Inverse permutation to A072787.

Original entry on oeis.org

0, 1, 3, 2, 8, 5, 4, 22, 7, 13, 10, 17, 18, 6, 9, 36, 21, 64, 19, 15, 12, 27, 46, 50, 16, 14, 41, 24, 31, 59, 58, 47, 60, 38, 37, 32, 11, 45, 20, 191, 44, 52, 120, 40, 23, 78, 63, 148, 144, 56, 43, 51, 111, 108, 35, 106, 61, 196, 168, 131, 178, 153, 150, 115, 116, 33, 29
Offset: 0

Views

Author

Antti Karttunen, Jun 12 2002

Keywords

Crossrefs

Inverse permutation: A072787. Cf. also A072740, A072741, A072789.
Showing 1-5 of 5 results.