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

 

Logo

Annual Appeal: Today, Nov 11 2014, is the 4th anniversary of the launch of the new OEIS web site. 70,000 sequences have been added in these four years, all edited by volunteers. Please make a donation (tax deductible in the US) to help keep the OEIS running.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A112886 Triangle-free positive integers. 9
1, 2, 4, 5, 7, 8, 11, 13, 14, 16, 17, 19, 22, 23, 25, 26, 29, 31, 32, 34, 35, 37, 38, 41, 43, 44, 46, 47, 49, 52, 53, 58, 59, 61, 62, 64, 65, 67, 68, 71, 73, 74, 76, 77, 79, 82, 83, 85, 86, 88, 89, 92, 94, 95, 97, 98, 101, 103, 104, 106, 107, 109, 113, 115, 116, 118, 119 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Those positive integers not in A113502.

a(n) = A132895(n)/2. - Ray Chandler, May 29 2008

LINKS

Table of n, a(n) for n=1..67.

EXAMPLE

14 is included because the divisors of 14 are 1, 2, 7 and 14, none of which are triangular numbers > 1.

MATHEMATICA

v={}; Do[If[b=Select[Divisors[n], #>1 && IntegerQ[(1+8#)^(1/2)]&]; b=={}, AppendTo[v, n]], {n, 138}]; v (Firoozbakht)

CROSSREFS

Cf. A113502, A000217, A005117.

Sequence in context: A188298 A206285 A229303 * A111040 A191324 A147807

Adjacent sequences:  A112883 A112884 A112885 * A112887 A112888 A112889

KEYWORD

nonn

AUTHOR

Leroy Quet, Jan 10 2006

EXTENSIONS

More terms from Farideh Firoozbakht, Jan 12 2006

STATUS

approved

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

Content is available under The OEIS End-User License Agreement .

Last modified November 25 15:28 EST 2014. Contains 249997 sequences.