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A286361
Least number with the same prime signature as {the largest divisor of n with only prime factors of the form 4k+1} has: a(n) = A046523(A170818(n)).
8
1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 2, 1, 2, 1, 2, 1, 1, 2, 1, 1, 1, 1, 4, 2, 1, 1, 2, 2, 1, 1, 1, 2, 2, 1, 2, 1, 2, 2, 2, 1, 1, 1, 2, 1, 1, 1, 1, 4, 2, 2, 2, 1, 2, 1, 1, 2, 1, 2, 2, 1, 1, 1, 6, 1, 1, 2, 1, 2, 1, 1, 2, 2, 4, 1, 1, 2, 1, 2, 1, 2, 1, 1, 6, 1, 2, 1, 2, 2, 2, 1, 1, 1, 2, 1, 2, 1, 1, 4, 2, 2, 1, 2, 2, 2, 1, 1, 2, 2, 2, 1, 2, 1, 2, 2, 2, 1, 2, 2
OFFSET
1,5
LINKS
FORMULA
a(n) = A046523(A170818(n)).
a(n) = A286363(A267099(n)).
PROG
(Scheme) (define (A286361 n) (A046523 (A170818 n)))
(Python)
from sympy import factorint
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 a072438(n):
f = factorint(n)
return 1 if n == 1 else reduce(mul, [1 if i%4==1 else i**f[i] for i in f])
def a(n): return a046523(n/a072438(n)) # Indranil Ghosh, May 09 2017
CROSSREFS
Differs from A063014 for the first time at n=25, where a(25) = 4, while A063014(25) = 3.
Sequence in context: A362845 A293451 A063014 * A357849 A097295 A220572
KEYWORD
nonn
AUTHOR
Antti Karttunen, May 08 2017
STATUS
approved