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A291634
Number of primitive sequences n = b_1 < b_2 < ... < b_t = A006255(n) such that b_1*b_2*...*b_t is a perfect square.
0
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 3, 1, 3, 1, 1, 1, 8, 1, 11, 1, 1, 2, 20, 1, 1, 2, 1, 1
OFFSET
1,11
COMMENTS
A primitive sequence is one such that no proper, nonempty subsequence has a product that is a perfect square.
Trivially, a(n) <= A259527(n). If A259527(n) = 1, then a(n) = 1.
MAPLE
For n = 22 the a(22) = 2 solutions are:
22 * 24 * 33 = 132^2, and
22 * 27 * 32 * 33 = 792^2.
Note that 22 * 24 * 25 * 33 = 660^2 is not a solution because the subsequence [25] has a square product.
CROSSREFS
Sequence in context: A274613 A066975 A355879 * A098877 A225212 A091088
KEYWORD
nonn,more
AUTHOR
Peter Kagey, Aug 29 2017
STATUS
approved