A103276 - OEIS

A103276

a(n) = (prime(n+1) + prime(k))/prime(n), where k is the smallest number such that prime(n+1) + prime(k)==0 mod prime(n), n+1 < k.

4, 4, 4, 4, 4, 6, 6, 4, 6, 12, 6, 4, 10, 6, 6, 12, 6, 8, 4, 4, 6, 4, 6, 12, 12, 6, 12, 24, 6, 12, 6, 8, 4, 22, 6, 8, 8, 6, 6, 6, 10, 10, 4, 10, 6, 6, 12, 10, 30, 4, 12, 6, 22, 6, 6, 12, 12, 14, 4, 12, 4, 6, 6, 6, 16, 4, 8, 10, 4, 6, 6, 4, 20, 24, 10, 14, 12, 4, 6, 4

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OFFSET

1,1

LINKS

Table of n, a(n) for n=1..80.

EXAMPLE

a(1) = (prime(2) + prime(k))/prime(1) = (3+5)/2 = 4.

MAPLE

A103276 := proc(n) local p, q, r, i ; p := ithprime(n) ; q := ithprime(n+1) ; r := 2 ; for i from 1 do if ( q+r ) mod p = 0 and r>q then RETURN ((q+r)/p) ; fi ; r := nextprime(r) ; od: end: seq(A103276(n), n=1..80) ; # R. J. Mathar, Mar 06 2008

CROSSREFS

Sequence in context: A247969 A091844 A244157 * A059190 A085142 A064053

Adjacent sequences: A103273 A103274 A103275 * A103277 A103278 A103279

KEYWORD

nonn

AUTHOR

Yasutoshi Kohmoto, Jan 27 2005

EXTENSIONS

Corrected and extended by R. J. Mathar, Mar 06 2008

STATUS

approved