login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A233421 Let m = n-th nonsquare = A000037(n); then a(n) = A006255(m). 2
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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Peter Kagey, Table of n, a(n) for n = 1..5000

AoPS Forum, 2013 Putnam Contest, Problem A2, Dec 08 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]

FORMULA

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

EXAMPLE

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.

CROSSREFS

Arguments are numbers that are nonsquares: A000037.

This is A006255 with perfect squares omitted.

Sequence in context: A000379 A176525 A065985 * A060652 A020739 A064466

Adjacent sequences:  A233418 A233419 A233420 * A233422 A233423 A233424

KEYWORD

nonn

AUTHOR

Peter Kagey, Dec 09 2013

EXTENSIONS

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

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified June 15 20:42 EDT 2019. Contains 324144 sequences. (Running on oeis4.)