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A286584 a(n) = A048673(n) mod 4. 5
1, 2, 3, 1, 0, 0, 2, 2, 1, 3, 3, 3, 1, 1, 2, 1, 2, 2, 0, 0, 0, 0, 3, 0, 1, 2, 3, 2, 0, 1, 3, 2, 1, 1, 3, 1, 1, 3, 3, 3, 2, 3, 0, 3, 0, 0, 3, 3, 1, 2, 0, 1, 2, 0, 2, 1, 2, 3, 3, 2, 2, 0, 2, 1, 0, 2, 0, 2, 1, 0, 1, 2, 0, 2, 3, 0, 0, 0, 2, 0, 1, 1, 1, 0, 3, 3, 2, 0, 1, 3, 2, 3, 1, 0, 1, 0, 3, 2, 3, 1, 0, 3, 2, 2, 1, 1, 3, 3, 1, 1, 3, 2, 0 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..10000

FORMULA

a(n) = A010873(A048673(n)) = A048673(n) mod 4.

PROG

(PARI)

A003961(n) = my(f = factor(n)); for (i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); \\ Using code of Michel Marcus

A048673(n) = (A003961(n)+1)/2;

A286584(n) = (A048673(n)%4);

(Scheme) (define (A286584 n) (modulo (A048673 n) 4))

(Python)

from sympy import factorint, nextprime

from operator import mul

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 a048673(n)%4 # Indranil Ghosh, Jun 12 2017

CROSSREFS

Cf. A010873, A048673, A286582, A286583, A286585.

Cf. A246261 (positions of odd terms), A246263 (of even terms).

Sequence in context: A070078 A054438 A261015 * A174947 A010341 A072772

Adjacent sequences:  A286581 A286582 A286583 * A286585 A286586 A286587

KEYWORD

nonn

AUTHOR

Antti Karttunen, May 31 2017

STATUS

approved

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Last modified April 1 14:52 EDT 2020. Contains 333163 sequences. (Running on oeis4.)