A233421 Let m = n-th nonsquare = A000037(n); then a(n) = A006255(m).

6, 8, 10, 12, 14, 15, 18, 22, 20, 26, 21, 24, 34, 27, 38, 30, 28, 33, 46, 32, 39, 35, 40, 58, 42, 62, 45, 44, 51, 48, 74, 57, 52, 50, 82, 56, 86, 55, 60, 69, 94, 54, 63, 68, 65, 106, 70, 66, 72, 76, 87, 118, 75, 122, 93, 77, 78, 80, 134, 85, 92, 84

Offset: 1

Author

Peter Kagey, Dec 09 2013

Keywords

• nonn

Examples

			a(1) = A006255(A000037(1)) = A006255(2) = 6 because 2*3*6 = 6^2.
a(2) = A006255(A000037(2)) = A006255(3) = 8 because 3*6*8 = 12^2.
		

Links

• Peter Kagey, Table of n, a(n) for n = 1..5000
• William Lowell Putnam Competition, Problem A2, 2013.
• R. L. Graham, Bijection between integers and composites, Problem 1242, Math. Mag., 60 (1987), p. 180. [Note that unless you subscribe to JSTOR this link will only show page 178, which contains a different problem proposed by R. L. Graham. - _N. J. A. Sloane_, Jan 13 2014]

Crossrefs

Arguments are numbers that are nonsquares: A000037.

This is A006255 with perfect squares omitted.

Formula

a(n) = A006255(A000037(n)). - Michel Marcus, Jan 07 2014

Extensions

Edited by Michel Marcus and N. J. A. Sloane, Jan 13 2014