login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A277494 a(n) = smallest m for which there is a sequence n = b_1 < b_2 <= b_3 <= ... <= b_t = m such that b_1*b_2*...*b_t is a perfect cube. 4
0, 1, 4, 6, 9, 10, 12, 14, 8, 16, 15, 22, 18, 26, 21, 20, 24, 34, 25, 38, 28, 30, 33, 46, 32, 35, 39, 27, 36, 58, 40, 62, 45, 44, 51, 42, 48, 74, 57, 52, 50, 82, 49, 86, 55, 54, 69, 94, 60, 56, 63, 68, 65, 106, 70, 66, 72, 76, 87, 118, 75, 122, 93, 77, 64, 78 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

A cube analog of R. L. Graham's sequence (A006255).

Like R. L. Graham's sequence, this is a bijection between the natural numbers and the nonprimes.

a(p) = 2p for all primes p.

LINKS

Peter Kagey, Table of n, a(n) for n = 0..5000

Peter Kagey, Examples of a(n) for n = 0..1000

EXAMPLE

a(0)  = 0  via 0                     =   0^3

a(1)  = 1  via 1                     =   1^3

a(2)  = 4  via 2 * 4                 =   2^3

a(3)  = 6  via 3 * 4^2 * 6^2         =  12^3

a(4)  = 9  via 4 * 6 * 9             =   6^3

a(5)  = 10 via 5 * 6 * 9 * 10^2      =  30^3

a(6)  = 12 via 6 * 9^2 * 12          =  18^3

a(7)  = 14 via 7 * 9^2 * 12^2 * 14^2 = 252^3

a(8)  = 8  via 8                     =   2^3

a(9)  = 16 via 9 * 12 * 16           =  12^3

a(10) = 15 via 10 * 12 * 15^2        =  30^3

CROSSREFS

Cf. A006255, A277278.

Sequence in context: A010404 A010447 A112082 * A174896 A304634 A319240

Adjacent sequences:  A277491 A277492 A277493 * A277495 A277496 A277497

KEYWORD

nonn

AUTHOR

Peter Kagey, Oct 17 2016

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 July 5 19:02 EDT 2020. Contains 335473 sequences. (Running on oeis4.)