OFFSET
1,2
COMMENTS
Greatest Fermi-Dirac factor of n: Largest divisor of n of the form p^(2^k), for some prime p and k >= 0, with a(1) = 1. Thus for n > 1, the largest term of A050376 that divides n. - Antti Karttunen, Apr 13 2018
LINKS
Reinhard Zumkeller, Table of n, a(n) for n = 1..10000
OEIS Wiki, "Fermi-Dirac representation" of n
FORMULA
MATHEMATICA
f[p_, e_] := p^(2^Floor[Log2[e]]); a[n_] := Max @@ f @@@ FactorInteger[n]; Array[a, 100] (* Amiram Eldar, Nov 26 2020 *)
PROG
(Haskell)
a223491 = last . a213925_row
(PARI)
ispow2(n) = (n && !bitand(n, n-1));
A223491(n) = if(1==n, n, fordiv(n, d, if(ispow2(isprimepower(n/d)), return(n/d)))); \\ Antti Karttunen, Apr 13 2018
CROSSREFS
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Mar 20 2013
STATUS
approved