OFFSET
1,3
COMMENTS
First time a term appears four or more times in a row is when n = 1684.
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
Jan Misali, What should we call the other bases?, Web page, no date. Inspiration for this sequence.
FORMULA
EXAMPLE
The prime factorization of 44 is 2^2 * 11^1, so a(44) = 2^2 * 10^1 = 40.
The prime factorization of 50 is 2^1 * 5^2, so a(50) = 2^1 * 4^2 = 32.
MATHEMATICA
a[n_] := Module[{f = FactorInteger[n]}, n*(1 - 1/f[[-1, 1]])^f[[-1, 2]]]; a[1] = 1; Array[a, 100] (* Amiram Eldar, Feb 04 2022 *)
PROG
(PARI) a(n) = my(f=factor(n), r=matsize(f)[1]); if(r, f[r, 1]--); factorback(f); \\ Kevin Ryde, Feb 03 2022
CROSSREFS
KEYWORD
nonn
AUTHOR
Ben Polson, Feb 03 2022
EXTENSIONS
a(1) = 1 prepended by Michel Marcus, Feb 04 2022
Edited by N. J. A. Sloane, Feb 11 2022
STATUS
approved