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A117102 Least n such that nextprime(p*n)>p*nextprime(n) where p traversing prime numbers (if p is prime then nextprime(p)=p). 0
4, 16, 18, 42, 126, 126, 136, 70, 58, 292, 822, 1872, 1446, 1008, 3318, 2026, 2280, 2842, 7726, 17922, 2136, 5022, 20142, 17550, 19540, 68898, 59082, 18792, 90006, 136540, 246888, 392382, 197088, 144060, 819898, 137956, 1555162, 291198, 909772 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

A(n)+1 is always prime ? A(n) is always even ?

LINKS

Table of n, a(n) for n=0..38.

EXAMPLE

for p=2 least n such than f(2*n)>2*f(n) and n is composite is 4=a(1)

for p=3 least n such than f(3*n)>3*f(n) and n is composite is 16=a(2)

PROG

(PARI) f(n)=nextprime(n); g(n, a)=for(i=1, a, if(f(n*i)>f(n)*f(i) && !isprime(i), return(i))); forprime (i=1, 150, print1(g(i, 5000000), ", "))

CROSSREFS

Sequence in context: A224705 A243298 A139719 * A077476 A282552 A278315

Adjacent sequences:  A117099 A117100 A117101 * A117103 A117104 A117105

KEYWORD

easy,nonn

AUTHOR

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

STATUS

approved

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Last modified May 27 06:24 EDT 2019. Contains 323599 sequences. (Running on oeis4.)