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%I #5 Jan 03 2021 00:59:03
%S 4,16,18,42,126,126,136,70,58,292,822,1872,1446,1008,3318,2026,2280,
%T 2842,7726,17922,2136,5022,20142,17550,19540,68898,59082,18792,90006,
%U 136540,246888,392382,197088,144060,819898,137956,1555162,291198,909772
%N Least n such that nextprime(p*n) > p*nextprime(n) where p runs through the prime numbers (if p is prime then nextprime(p)=p).
%C Is a(n)+1 always prime? Is a(n) always even?
%e For p=2 least n such that f(2*n) > 2*f(n) and n is composite is 4=a(1);
%e for p=3 least n such that f(3*n) > 3*f(n) and n is composite is 16=a(2).
%o (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),","))
%K easy,nonn
%O 0,1
%A Mohammed Bouayoun (mohammed.bouayoun(AT)sanef.com), Apr 18 2006
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