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.

A072786 Differences between A072782 and A072739.

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Jun 12 2002

Keywords

Programs

A072733 Simple triangle-stretching N X N -> N bijection: Inverse of A072732.

Original entry on oeis.org

0, 1, 5, 6, 2, 14, 15, 3, 9, 27, 28, 10, 4, 20, 44, 45, 21, 7, 13, 35, 65, 66, 36, 16, 8, 26, 54, 90, 91, 55, 29, 11, 19, 43, 77, 119, 120, 78, 46, 22, 12, 34, 64, 104, 152, 153, 105, 67, 37, 17, 25, 53, 89, 135, 189, 190, 136, 92, 56, 30, 18, 42, 76, 118, 170, 230, 231
Offset: 0

Views

Author

Antti Karttunen, Jun 12 2002

Keywords

Crossrefs

Inverse: A072732, projections: A072738 & A072739, variant of the same theme: A072735. Cf. also A001477 and its projections A025581 & A002262.

Programs

  • Scheme
    (define (A072733 n) (packA072733 (A025581 n) (A002262 n)))
    (define (packA001477 x y) (/ (+ (expt (+ x y) 2) x (* 3 y)) 2))
    (define (packA072733 x y) (cond ((<= x y) (let ((half-x (floor->exact (/ x 2)))) (packA001477 half-x (+ half-x (* 2 (- y (* 2 half-x) (modulo x 2))) (modulo x 2))))) (else (let ((half-y (floor->exact (/ y 2)))) (packA001477 (+ 1 half-y (* 2 (- (-1+ x) (* 2 half-y) (modulo y 2))) (modulo y 2)) half-y)))))

A072738 X-projection of the tabular N X N -> N bijection A072733.

Original entry on oeis.org

0, 1, 1, 2, 2, 0, 2, 3, 3, 1, 3, 4, 4, 2, 0, 3, 4, 5, 5, 3, 1, 4, 5, 6, 6, 4, 2, 0, 4, 5, 6, 7, 7, 5, 3, 1, 5, 6, 7, 8, 8, 6, 4, 2, 0, 5, 6, 7, 8, 9, 9, 7, 5, 3, 1, 6, 7, 8, 9, 10, 10, 8, 6, 4, 2, 0, 6, 7, 8, 9, 10, 11, 11, 9, 7, 5, 3, 1, 7, 8, 9, 10, 11, 12, 12, 10, 8, 6, 4, 2, 0, 7, 8, 9, 10, 11, 12, 13
Offset: 0

Views

Author

Antti Karttunen, Jun 12 2002

Keywords

Crossrefs

The Y-projection is A072739. Composition of A025581 & A072732. A072785(n) = A072781(n)-A072738(n).

Programs

A072782 Y-projection of the tabular N X N -> N bijection A072735.

Original entry on oeis.org

0, 0, 1, 0, 2, 1, 1, 2, 3, 2, 0, 2, 4, 3, 2, 1, 3, 4, 5, 4, 3, 0, 2, 4, 6, 5, 4, 3, 1, 3, 5, 6, 7, 6, 5, 4, 0, 2, 4, 6, 8, 7, 6, 5, 4, 1, 3, 5, 7, 8, 9, 8, 7, 6, 5, 0, 2, 4, 6, 8, 10, 9, 8, 7, 6, 5, 1, 3, 5, 7, 9, 10, 11, 10, 9, 8, 7, 6, 0, 2, 4, 6, 8, 10, 12, 11, 10, 9, 8, 7, 6, 1, 3, 5, 7, 9, 11, 12, 13
Offset: 0

Views

Author

Antti Karttunen, Jun 12 2002

Keywords

Crossrefs

The X-projection is A072781. Composition of A002262 and A072734. A072786(n) = A072782(n)-A072739(n).

Programs

Showing 1-4 of 4 results.