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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A080431 Even numbers such that all a(i)*a(j) are distinct. 2
2, 4, 6, 8, 10, 14, 18, 22, 26, 32, 34, 38, 46, 50, 58, 60, 62, 74, 82, 86, 94, 98, 106, 118, 122, 134, 142, 146, 158, 162, 166, 168, 178, 194, 202, 206, 214, 218, 226, 242, 254, 256, 262, 274, 278, 298, 302, 308, 314, 326, 334, 338, 346, 358, 360, 362, 382, 386 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..58.

MAPLE

S := {8}: A := array(1..10^3): for m from 1 to 10^3 do A[m] := 0 od: A[2] := 2: A[4] := 4: for n from 6 to 10^3 by 2 do mytest := 0: for j from 2 to n-2 by 2 do if A[j]>0 then if member(A[j]*n, S) then mytest := 1; break; fi: fi: od: if mytest=0 then A[n] := n; for j from 2 to n-2 by 2 do S := S union {A[j]*n} od: fi: od: for i from 2 to 10^3 by 2 do if A[i]>0 then printf(`%d, `, A[i]) fi: od: # James A. Sellers, Feb 26 2003

CROSSREFS

Cf. A080430, A080432.

Equals 2*A066724.

Sequence in context: A151566 A160406 A113293 * A288732 A122642 A305703

Adjacent sequences:  A080428 A080429 A080430 * A080432 A080433 A080434

KEYWORD

nonn

AUTHOR

Amarnath Murthy, Feb 20 2003

EXTENSIONS

More terms from James A. Sellers, Feb 26 2003

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 March 26 22:42 EDT 2019. Contains 321565 sequences. (Running on oeis4.)