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.

A284004 a(n) = A046523(A284003(n)).

Original entry on oeis.org

1, 2, 6, 2, 30, 6, 2, 6, 210, 30, 6, 30, 2, 6, 30, 6, 2310, 210, 30, 210, 6, 30, 210, 30, 2, 6, 30, 6, 210, 30, 6, 30, 30030, 2310, 210, 2310, 30, 210, 2310, 210, 6, 30, 210, 30, 2310, 210, 30, 210, 2, 6, 30, 6, 210, 30, 6, 30, 2310, 210, 30, 210, 6, 30, 210, 30, 510510, 30030, 2310, 30030, 210, 2310, 30030, 2310, 30, 210, 2310, 210, 30030, 2310, 210, 2310
Offset: 0

Views

Author

Antti Karttunen, Mar 18 2017

Keywords

Crossrefs

Programs

  • Mathematica
    Table[Times @@ MapIndexed[Prime[First@ #2]^#1 &, Reverse@ Sort@ FactorInteger[#][[All, -1]]] - Boole[# == 1] &@ Apply[Times, FactorInteger[#] /. {p_, e_} /; e > 0 :> Times @@ (p^Mod[e, 2])] &[Times @@ Map[#1^#2 & @@ # &, FactorInteger[#] /. {p_, e_} /; e == 1 :> {Times @@ Prime@ Range@ PrimePi@ p, e}] &[Times @@ Prime@ Flatten@ Position[#, 1] &@ Reverse@ IntegerDigits[n, 2]]], {n, 0, 52}] (* Michael De Vlieger, Mar 18 2017 *)
  • PARI
    \\ Code for A284003 given under that entry.
    A046523(n) = my(f=vecsort(factor(n)[, 2], , 4), p); prod(i=1, #f, (p=nextprime(p+1))^f[i]) \\ From Charles R Greathouse IV, Aug 17 2011
    A284004(n) = A046523(A284003(n));
    
  • Scheme
    (define (A284004 n) (A046523 (A284003 n)))

Formula

a(n) = A046523(A284003(n)).
a(n) = A002110(A001222(A284003(n))) = A002110(A209281(n+1)). [Latter so far only conjectured.]