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A161537 a(n) = n-th composite + n. 2
5, 8, 11, 13, 15, 18, 21, 23, 25, 28, 31, 33, 35, 38, 40, 42, 44, 46, 49, 52, 54, 56, 58, 60, 63, 65, 67, 70, 73, 75, 77, 80, 82, 84, 86, 88, 91, 93, 95, 97, 99, 102, 105, 107, 109, 111, 113, 116, 118, 120, 123, 126, 128, 130, 132, 134, 137, 139, 141, 144, 146, 148, 150 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Complement of A171511. [Jaroslav Krizek, Dec 13 2009]

LINKS

Robert Israel, Table of n, a(n) for n = 1..10000

FORMULA

a(n) = A002808(n) + n = A002808(n) + A000027(n). [Jaroslav Krizek, Dec 10 2009]

EXAMPLE

a(1) = composite(1)+1 = 4 +1 = 5 ; a(2) = composite(2)+2 = 6+2=8.

MAPLE

Comps:= remove(isprime, [$4..200]):

seq(Comps[i]+i, i=1..nops(Comps)); # Robert Israel, Mar 23 2020

MATHEMATICA

c=0; Do[If[CompositeQ[n], c=c+1; Print[c+n]], {n, 1, 87}] (* Metin Sariyar, Mar 23 2020 *)

Range@ Length # + # &@ Select[Range[4, 87], CompositeQ] (* Michael De Vlieger, Mar 23 2020 *)

PROG

(PARI) my(n=0); forcomposite(k=4, 86, print1(k+n++, ", ")) \\ Hugo Pfoertner, Mar 23 2020

CROSSREFS

Cf. A002808, A171511.

Sequence in context: A246371 A274939 A173977 * A248634 A189724 A220143

Adjacent sequences:  A161534 A161535 A161536 * A161538 A161539 A161540

KEYWORD

nonn

AUTHOR

Claudio Meller, Jun 13 2009

STATUS

approved

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Last modified October 26 02:14 EDT 2021. Contains 348256 sequences. (Running on oeis4.)