

A259527


a(n) gives the number of sequences n = b_1 < b_2 < ... < b_t = A006255(n) such that b_1*b_2*...*b_t is a perfect square.


6



1, 2, 2, 1, 2, 2, 2, 2, 1, 2, 8, 2, 16, 2, 2, 1, 64, 2, 128, 4, 2, 4, 512, 2, 1, 4, 1, 2, 8192, 2, 8192, 4, 2, 16, 2, 1, 65536, 64, 4, 2, 524288, 8, 1048576, 4, 4, 128, 8388608, 2, 1, 1, 8, 2, 67108864, 4, 2, 2, 4, 256, 536870912, 2, 2147483648, 2048, 2, 1, 1
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OFFSET

1,2


COMMENTS

All terms are powers of 2.


LINKS

Peter Kagey, Table of n, a(n) for n = 1..1000


EXAMPLE

For a(20)=4 the solutions are:
s_0 = {20,24,30} with prod(s_0) = 120^2;
s_1 = {20,24,25,30} with prod(s_1) = 600^2;
s_2 = {20,21,24,27,28,30} with prod(s_2) = 15120^2;
s_3 = {20,21,24,25,27,28,30} with prod(s_3) = 75600^2.


CROSSREFS

Cf. A006255, A260510.
Sequence in context: A234305 A339701 A304094 * A275992 A271824 A253589
Adjacent sequences: A259524 A259525 A259526 * A259528 A259529 A259530


KEYWORD

nonn


AUTHOR

Peter Kagey, Jun 29 2015


EXTENSIONS

More terms from Alois P. Heinz, Jul 16 2015


STATUS

approved



