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.

A153880 Shift factorial base representation left by one digit.

Original entry on oeis.org

0, 2, 6, 8, 12, 14, 24, 26, 30, 32, 36, 38, 48, 50, 54, 56, 60, 62, 72, 74, 78, 80, 84, 86, 120, 122, 126, 128, 132, 134, 144, 146, 150, 152, 156, 158, 168, 170, 174, 176, 180, 182, 192, 194, 198, 200, 204, 206, 240, 242, 246, 248, 252, 254, 264, 266, 270, 272
Offset: 0

Views

Author

Antti Karttunen, Jan 03 2009

Keywords

Comments

Equally, append 0 to the end of the factorial base representation of n (= A007623(n)), then convert back to decimal.
Involution A225901 maps each term of this sequence to a unique term of A255411, and vice versa.

Examples

			Factorial base representation of 5 is A007623(5) = "21". Shifting this once left (that is, appending 0 to the end) yields "210", which is factorial base representation for 14. Thus a(5) = 14.
		

Crossrefs

Indices of zeros in A260736.
Cf. A153883 (terms divided by 2).
Cf. A266193 (a left inverse).
Cf. A273670 (complement).
Cf. also A007623, A225901, A255411.

Programs

  • Mathematica
    Table[Function[b, FromDigits[IntegerDigits[n, b]~Join~{0}, b]]@ MixedRadix[Reverse@ Range@ 12], {n, 0, 57}] (* Michael De Vlieger, May 30 2016, Version 10.2 *)
  • Python
    from sympy import factorial as f
    def a007623(n, p=2): return n if n
  • Scheme
    (define (A153880 n) (let loop ((n n) (z 0) (i 2) (f 2)) (cond ((zero? n) z) (else (loop (floor->exact (/ n i)) (+ (* f (modulo n i)) z) (+ 1 i) (* f (+ i 1)))))))
    

Formula

Other identities. For all n >= 0:
A266193(a(n)) = n.