|
| |
|
|
A100549
|
|
Let n = 2^e_2 * 3^e_ * 5^e_ * ... be the prime factorization of n; then a(n) = largest prime <= 1 + max{e_2, e_3, e_5, ...}; a(1) = 1 by convention.
|
|
6
| |
|
|
1, 2, 2, 3, 2, 2, 2, 3, 3, 2, 2, 3, 2, 2, 2, 5, 2, 3, 2, 3, 2, 2, 2, 3, 3, 2, 3, 3, 2, 2, 2, 5, 2, 2, 2, 3, 2, 2, 2, 3, 2, 2, 2, 3, 3, 2, 2, 5, 3, 3, 2, 3, 2, 3, 2, 3, 2, 2, 2, 3, 2, 2, 3, 7, 2, 2, 2, 3, 2, 2, 2, 3, 2, 2, 3, 3, 2, 2, 2, 5, 5, 2, 2, 3, 2, 2, 2, 3, 2, 3, 2, 3, 2, 2, 2, 5, 2, 3, 3, 3, 2, 2, 2, 3, 2
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,2
|
|
|
LINKS
| David Applegate and N. J. A. Sloane, Table of n, a(n) for n = 1..10000
|
|
|
EXAMPLE
| If n = 8 = 2^3, a(n) = (largest prime <= 3+1) = 3.
If n = 480 = 2^5*3*5, a(n) = (largest prime <= 1 + max{5,1,1}) = 5.
|
|
|
MAPLE
| # if n = prod_p p^e_p, then
# pp = largest prime <= 1 + max e_p
with(numtheory):
pp := proc(n) local f, m; option remember;
if (n = 1) then
return 1;
end if;
m := 1:
for f in op(2..-1, ifactors(n)) do
if (f[2] > m) then
m := f[2]:
end if;
end do;
prevprime(m+2);
end proc;
|
|
|
CROSSREFS
| Cf. A100762, A100417, A141586, A082725.
Sequence in context: A104517 A098397 A082091 * A085962 A160821 A060244
Adjacent sequences: A100546 A100547 A100548 * A100550 A100551 A100552
|
|
|
KEYWORD
| nonn
|
|
|
AUTHOR
| David Applegate and N. J. A. Sloane (njas(AT)research.att.com), Sep 15 2008
|
| |
|
|
