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A117103 Let p = n-th prime. Then a(n) = least odd composite number m such that nextprime(p*m) > p*nextprime(m). 1
27, 39, 105, 279, 629, 597, 1661, 1875, 3777, 13961, 15491, 33585, 87401, 11445, 28877, 113451, 265115, 146189, 584705, 668525, 1370667, 1582581, 1471865, 2193351, 2932901, 3832635, 3571617, 3617721, 15131459, 31245831, 11442269 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

If k is prime then nextprime(k)=k.

LINKS

Ray Chandler, Table of n, a(n) for n=1..32

EXAMPLE

For n = 1, p=2, least odd composite m such than f(2*m)>2*f(m) is 27=a(1).

PROG

(PARI) f(n)=nextprime(n); g(n, a)=for(i=1, a, if(f(n*i)>f(n)*f(i) && !isprime(i) && Mod(i, 2)!=0, return(i))); forprime (i=1, 150, print1(g(i, 500000000), ", "))

CROSSREFS

Sequence in context: A097228 A039614 A181489 * A217008 A124940 A272829

Adjacent sequences:  A117100 A117101 A117102 * A117104 A117105 A117106

KEYWORD

nonn

AUTHOR

Mohammed Bouayoun (mohammed.bouayoun(AT)sanef.com), Apr 18 2006

EXTENSIONS

a(26)-a(30) from Zak Seidov, May 15 2007

a(31)-a(32) from Ray Chandler, May 30 2007

STATUS

approved

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Last modified May 25 19:29 EDT 2019. Contains 323576 sequences. (Running on oeis4.)