OFFSET
1,2
COMMENTS
This sequence works as a "sentinel" for sequence A048673 by matching to any other sequence that is obtained as f(A048673(n)), where f(n) is any function that depends only on the prime signature of n (see the index entry for "sequences computed from exponents in ..."). As of Nov 11 2016 no such sequences were present in the database.
LINKS
PROG
(Python)
from sympy import factorint, nextprime
from operator import mul
def P(n):
f = factorint(n)
return sorted([f[i] for i in f])
def a046523(n):
x=1
while True:
if P(n) == P(x): return x
else: x+=1
def a048673(n):
f = factorint(n)
return 1 if n==1 else (1 + reduce(mul, [nextprime(i)**f[i] for i in f]))//2
def a(n): return a046523(a048673(n))
print([a(n) for n in range(1, 101)]) # Indranil Ghosh, Jun 12 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Nov 16 2016
STATUS
approved