|
| |
|
|
A118499
|
|
Numbers n such that the n-th prime number is not a Chen prime.
|
|
0
| |
|
|
14, 18, 21, 22, 25, 27, 36, 38, 40, 44, 48, 50, 53, 58, 59, 61, 65, 67, 70, 73, 74, 76, 78, 82, 84, 85, 88, 90, 99, 101, 108, 110, 111, 112, 114, 117, 121, 122, 125, 127, 129, 130, 131, 134, 137, 143, 147, 149, 153, 155, 158, 163, 168, 170
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,1
|
|
|
EXAMPLE
| 97 is a prime number but not a Chen prime since 99 = 3*3*11.
97 is the 25th prime number, therefore 25 is in the sequence.
|
|
|
MAPLE
| ts_inde_nonchen:= proc(n) local i, ans, inde; ans:=[ ]: inde := 0; for i from 1 to n do if ( isprime(i) = 'true') then inde:=inde+1: if (isprime(i+2) = 'false' and numtheory[bigomega](i+2) <> 2) then ans:=[ op(ans), inde ] fi fi od: return ans end: ts_inde_nonchen(2000);
|
|
|
MATHEMATICA
| Select[Range[180], Sum[FactorInteger[Prime[ # ]+2][[i, 2]], {i, 1, Length[ FactorInteger[Prime[ # ] + 2]]}] > 2 &]
|
|
|
CROSSREFS
| Cf. A102540, A109611.
Sequence in context: A063828 A060504 A052026 * A111205 A097324 A051419
Adjacent sequences: A118496 A118497 A118498 * A118500 A118501 A118502
|
|
|
KEYWORD
| nonn
|
|
|
AUTHOR
| Jani Melik (jani_melik(AT)hotmail.com), May 05 2006
|
|
|
EXTENSIONS
| Edited by Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Jul 19 2007
|
| |
|
|
