|
| |
|
|
A061228
|
|
a(1) = 2, a(n) = smallest number greater than n which is not coprime to n.
|
|
7
| |
|
|
2, 4, 6, 6, 10, 8, 14, 10, 12, 12, 22, 14, 26, 16, 18, 18, 34, 20, 38, 22, 24, 24, 46, 26, 30, 28, 30, 30, 58, 32, 62, 34, 36, 36, 40, 38, 74, 40, 42, 42, 82, 44, 86, 46, 48, 48, 94, 50, 56, 52, 54, 54, 106, 56, 60, 58, 60, 60, 118, 62, 122, 64, 66, 66, 70, 68, 134, 70, 72, 72
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 0,1
|
|
|
FORMULA
| a(2m) = 2m+2, a(p)= 2p if p is a prime.
a(n)= n + the smallest divisor (more than 1) of n.
|
|
|
EXAMPLE
| a(9) = 12 as 10 and 11 are coprime to 9. a(11) = 22. as 11 is a prime.
|
|
|
MAPLE
| for n from 1 to 150 do if n=1 then printf(`%d, `, 2); fi: for k from n+1 to 2*n do if igcd(n, k)>1 then printf(`%d, `, k); break; fi: od: od:
|
|
|
MATHEMATICA
| Table[n+First@(First/@FactorInteger[n]), {n, 200}] (*From Vladimir Joseph Stephan Orlovsky, Apr 8 2011*)
|
|
|
CROSSREFS
| Cf. A046666, A020639(n+1) + n.
Sequence in context: A159276 A056942 A115947 * A070229 A053568 A037225
Adjacent sequences: A061225 A061226 A061227 * A061229 A061230 A061231
|
|
|
KEYWORD
| nonn
|
|
|
AUTHOR
| Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Apr 23 2001
|
|
|
EXTENSIONS
| More terms from James A. Sellers (sellersj(AT)math.psu.edu), Apr 24 2001
|
| |
|
|
