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A118499 Numbers k such that the k-th prime number is not a Chen prime. 1
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; text; internal format)
OFFSET

1,1

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000

EXAMPLE

97 is the 25th prime number but not a Chen prime since 99 = 3*3*11, 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 &]

PROG

(PARI) isok(k) = (bigomega(prime(k)+2) > 2); \\ Michel Marcus, Oct 19 2021

CROSSREFS

Cf. A102540, A109611.

Sequence in context: A060504 A052026 A317743 * A111205 A097324 A051419

Adjacent sequences:  A118496 A118497 A118498 * A118500 A118501 A118502

KEYWORD

nonn

AUTHOR

Jani Melik, May 05 2006

EXTENSIONS

Edited by Stefan Steinerberger, Jul 19 2007

STATUS

approved

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Last modified August 7 23:50 EDT 2022. Contains 355995 sequences. (Running on oeis4.)