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A353415
Number of ways to write the square of n as a product of the terms of A353355 larger than 1; a(1) = 1 by convention (an empty product).
2
1, 1, 1, 1, 1, 3, 1, 3, 1, 2, 1, 6, 1, 3, 3, 5, 1, 6, 1, 5, 2, 2, 1, 14, 1, 3, 3, 6, 1, 12, 1, 6, 3, 2, 3, 20, 1, 3, 2, 10, 1, 12, 1, 5, 6, 2, 1, 27, 1, 5, 3, 6, 1, 14, 2, 14, 2, 3, 1, 32, 1, 2, 5, 11, 3, 12, 1, 5, 3, 12, 1, 43, 1, 3, 6, 6, 3, 12, 1, 17, 5, 2, 1, 38, 2, 3, 2, 10, 1, 38, 2, 5, 3, 2, 3, 46, 1, 6, 6
OFFSET
1,6
COMMENTS
Number of factorizations of n^2 into factors k > 1 for which A353354(k) = 0.
FORMULA
a(n) = A353414(A000290(n)).
a(p) = 1 for all primes p.
a(n) = a(A003961(n)) = a(A348717(n)), for all n >= 1.
PROG
(PARI)
A332823(n) = { my(f = factor(n), u=(sum(k=1, #f~, f[k, 2]*2^primepi(f[k, 1]))/2)%3); if(2==u, -1, u); };
A353354(n) = sumdiv(n, d, A332823(d));
A353380(n) = (0==A353354(n));
A353414(n, m=n) = if(1==n, 1, my(s=0); fordiv(n, d, if((d>1)&&(d<=m)&&A353380(d), s += A353414(n/d, d))); (s));
A353415(n) = A353414(n^2);
KEYWORD
nonn
AUTHOR
Antti Karttunen, Apr 19 2022
STATUS
approved