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A064799 Sum of n-th prime number and n-th composite number. +0
4
6, 9, 13, 16, 21, 25, 31, 34, 39, 47, 51, 58, 63, 67, 72, 79, 86, 89, 97, 103, 106, 113, 118, 125, 135, 140, 143, 149, 153, 158, 173, 179, 186, 189, 200, 203, 211, 218, 223, 230, 237, 241, 253, 256, 261, 264, 277, 291, 296, 299, 305, 313, 316, 327, 334, 341 (list; graph; listen)
OFFSET

1,1

REFERENCES

Ivan Grischenko, ivansasha(AT)mtu-net.ru, private communication.

LINKS

Harry J. Smith, Table of n, a(n) for n=1,...,1000

FORMULA

a(n) = prime(n)+composite(n)

EXAMPLE

E.g. a(1)=6 because first prime is 2 and first composite is 4. a(2)=9 because p(2)=3 and c(2)=6. Et cetera.

PROGRAM

(PARI) nextComp(n)= { if (!isprime(n), return(n)); return(n + 1) } { p=1; c=3; for (n=1, 1000, p=nextprime(p + 1); c=nextComp(c + 1); write("b064799.txt", n, " ", p + c) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Sep 25 2009]

CROSSREFS

Sequence in context: A106218 A118521 A095213 this_sequence A030499 A167614 A020751

Adjacent sequences: A064796 A064797 A064798 this_sequence A064800 A064801 A064802

KEYWORD

nonn,easy

AUTHOR

Konstantin Knop (Konstantin(AT)Knop.com), Oct 21 2001

EXTENSIONS

More terms from Larry Reeves (larryr(AT)acm.org), Nov 12 2001

OFFSET changed from 0,1 to 1,1 by Harry J. Smith (hjsmithh(AT)sbcglobal.net), Sep 25 2009

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Last modified November 24 14:25 EST 2009. Contains 167438 sequences.


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