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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.

A276009 Decrement each nonzero digit by one in factorial base representation of n: a(n) = n - A276008(n).

Original entry on oeis.org

0, 0, 0, 0, 2, 2, 0, 0, 0, 0, 2, 2, 6, 6, 6, 6, 8, 8, 12, 12, 12, 12, 14, 14, 0, 0, 0, 0, 2, 2, 0, 0, 0, 0, 2, 2, 6, 6, 6, 6, 8, 8, 12, 12, 12, 12, 14, 14, 24, 24, 24, 24, 26, 26, 24, 24, 24, 24, 26, 26, 30, 30, 30, 30, 32, 32, 36, 36, 36, 36, 38, 38, 48, 48, 48, 48, 50, 50, 48, 48, 48, 48, 50, 50, 54, 54, 54, 54, 56, 56, 60, 60, 60, 60, 62, 62, 72, 72, 72, 72
Offset: 0

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Author

Antti Karttunen, Aug 18 2016

Keywords

Examples

			For n=23 whose factorial base representation is "321", when we subtract one from each digit we get "210", the factorial base representation of 14, thus a(23) = 14.
For n=37 ("1201"), when we subtract one from each digit we get "0100", thus a(37) = 6 as A007623(6) = 100.
		

Crossrefs

Programs

  • Mathematica
    a[n_] := Module[{k = n, m = 2, r, s = {}}, While[{k, r} = QuotientRemainder[k, m]; k != 0|| r != 0, AppendTo[s, r]; m++]; s = Max[# - 1, 0]& /@ s; Total[s*Range[Length[s]]!]]; Array[a, 100, 0] (* Amiram Eldar, Feb 14 2024 *)
  • Python
    from sympy import factorial as f
    def a007623(n, p=2): return n if n

    0 else '0' for i in x)[::-1] return sum([int(y[i])*f(i + 1) for i in range(len(y))]) print([a(n) for n in range(201)]) # Indranil Ghosh, Jun 21 2017

  • Scheme
    (define (A276009 n) (- n (A276008 n)))
    ;; Standalone version:
    (define (A276009 n) (let loop ((n n) (s 0) (f 1) (i 2)) (if (zero? n) s (let ((d (modulo n i))) (if (zero? d) (loop (/ n i) s (* i f) (+ 1 i)) (loop (/ (- n d) i) (+ s (* f (- d 1))) (* i f) (+ 1 i)))))))
    

Formula

a(n) = n - A276008(n).