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.

A289660 a(n) = A037276(n) - n.

Original entry on oeis.org

0, 0, 0, 18, 0, 17, 0, 214, 24, 15, 0, 211, 0, 13, 20, 2206, 0, 215, 0, 205, 16, 189, 0, 2199, 30, 187, 306, 199, 0, 205, 0, 22190, 278, 183, 22, 2197, 0, 181, 274, 2185, 0, 195, 0, 2167, 290, 177, 0, 22175, 28, 205, 266, 2161, 0, 2279, 456, 2171, 262, 171, 0, 2175, 0, 169, 274, 222158, 448, 2245, 0
Offset: 1

Views

Author

N. J. A. Sloane, Jul 24 2017

Keywords

Comments

The fact that a(n)>0 if n is composite shows that (unlike A080670), A037276 has no nontrivial fixed points (nor any cycles).

Crossrefs

Programs

  • Mathematica
    FromDigits@Flatten@IntegerDigits[Table[#1,{#2}]&@@@FactorInteger@#]-#&/@Range@54 (* Vincenzo Librandi, Jul 25 2017 *)
  • Python
    from sympy import factorint
    def A289660(n):
        return 0 if n == 1 else int(''.join(map(lambda x: str(x[0])*x[1],sorted(factorint(n).items())))) - n # Chai Wah Wu, Jul 25 2017