[seqfan] Re: Is this right? Main diagonal A[n.n] of array A[k, n] = n-th natural number m such that m and m+2 are both divisible by exactly k primes (counted with multiplicity).
Ray Chandler
rayjchandler at sbcglobal.net
Fri Aug 13 18:55:34 CEST 2010
> I agree, and think I have 14 and 15, so A[k,n=k] begins
>
> [3, 33, 42, 196, 918, 6640, 24750, 246078, 781248, 6565374,
> 25227774, 165009150, 673932798, 5268548608, 25737162750]
>
> using a crude sieve. The same dataset gives
>
> [3, 4, 18, 54, 270, 1888, 10528, 59776, 101248, 406782,
> 6581248, 12164094, 65071998, 652963840, 6548416000, 13858918398]
>
> for A[k,1], although I think this could be found much faster
> than I'm doing it.
>
>
> Doug
>
It appears A[k+1,1] = 2*A115186(k) so I'm guessing it continues
{3, 4, 18, 54, 270, 1888, 10528, 59776, 101248, 406782, 6581248,
12164094, 65071998, 652963840, 6548416000, 13858918398, 145046192128,
75389157376, 943344975870, 23114453401600, 108772434771966,
101249475018750, 551785225781248}
Ray
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