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.

A231714 Lower triangular region of A231713; A triangular table read by rows: T(n,k) = sum of absolute values of digit differences in the factorial base representations (A007623) of n and k, where (n, k) = (0,0), (1,0), (1,1), (2,0), (2,1), (2,2), ..., n >= 0 and (0 <= k <= n).

Original entry on oeis.org

0, 1, 0, 1, 2, 0, 2, 1, 1, 0, 2, 3, 1, 2, 0, 3, 2, 2, 1, 1, 0, 1, 2, 2, 3, 3, 4, 0, 2, 1, 3, 2, 4, 3, 1, 0, 2, 3, 1, 2, 2, 3, 1, 2, 0, 3, 2, 2, 1, 3, 2, 2, 1, 1, 0, 3, 4, 2, 3, 1, 2, 2, 3, 1, 2, 0, 4, 3, 3, 2, 2, 1, 3, 2, 2, 1, 1, 0, 2, 3, 3, 4, 4, 5, 1, 2, 2, 3, 3, 4, 0, 3, 2, 4, 3, 5, 4, 2, 1, 3, 2, 4, 3, 1, 0, 3, 4, 2, 3, 3, 4, 2, 3, 1, 2, 2, 3, 1, 2, 0
Offset: 0

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Author

Antti Karttunen, Nov 12 2013

Keywords

Examples

			This triangular table begins as:
  0;
  1, 0;
  1, 2, 0;
  2, 1, 1, 0;
  2, 3, 1, 2, 0;
  3, 2, 2, 1, 1, 0;
  1, 2, 2, 3, 3, 4, 0;
  2, 1, 3, 2, 4, 3, 1, 0;
  ...
Please see A231713 for examples how the terms are computed.
		

Crossrefs

The leftmost column: A034968.
This is a lower, or equivalently, an upper triangular subregion of symmetric square array A231713. Cf. A230417.

Programs

  • Scheme
    (define (A231714 n) (A231713bi (A003056 n) (A002262 n)))
    (define (A231713bi x y) (let loop ((x x) (y y) (i 2) (d 0)) (cond ((and (zero? x) (zero? y)) d) (else (loop (floor->exact (/ x i)) (floor->exact (/ y i)) (+ i 1) (+ d (abs (- (modulo x i) (modulo y i)))))))))

Formula

a(n) = A231713(A003056(n),A002262(n)). [As a sequence, this is obtained by taking a subsection from array A231713.]
T(n,0) = A034968(n). [The leftmost column]
Each entry T(n,k) >= A230417(n,k).