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 A300737 Numbers of the form (k*i + 1)*(k*j - 1) with i, j >= 1 and k >= 2. 1

%I

%S 3,5,7,8,9,11,13,14,15,17,19,20,21,23,24,25,26,27,29,31,32,33,35,37,

%T 38,39,41,43,44,45,47,48,49,50,51,53,54,55,56,57,59,61,62,63,64,65,67,

%U 68,69,71,73,74,75,77,79,80,81,83,84,85,86,87,89,90,91,92,93,95,97,98,99,101

%N Numbers of the form (k*i + 1)*(k*j - 1) with i, j >= 1 and k >= 2.

%o (PARI) limit=100; v=vector(limit); for(n=0,limit, for(k=2,floor(limit^(1/2)), for(i=1,limit/k, for(j=1,limit/k,if(n==(k*i+1)*(k*j-1),v[n]=1,))))); for(n=1,limit,if(v[n],print1(n", ")))

%Y Cf. A056868.

%K nonn

%O 1,1

%A _Gionata Neri_, Mar 11 2018

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Last modified December 6 16:24 EST 2019. Contains 329808 sequences. (Running on oeis4.)