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A067356 Numbers n such that prime(n+3)-(n+3)*tau(n+3)=prime(n)-n*tau(n) where tau(n) is the number of divisors of n A000005(n). 0

%I

%S 172,206,435,542,551,575,611,626,718,759,903,955,1102,1238,1495,1711,

%T 2009,2379,2385,2482,2572,2815,2874,3018,3103,3222,3225,3802,3899,

%U 4055,4335,4342,4430,4439,4545,4682,5154,5183,5467,5594,6036,6058,6202,6231

%N Numbers n such that prime(n+3)-(n+3)*tau(n+3)=prime(n)-n*tau(n) where tau(n) is the number of divisors of n A000005(n).

%t ptQ[n_]:=Module[{n3=n+3},Prime[n3]-(n3)DivisorSigma[0,n3]==Prime[n]- n*DivisorSigma[ 0,n]]; Select[Range[6300],ptQ] (* _Harvey P. Dale_, Jul 22 2012 *)

%Y Cf. A000005.

%K easy,nonn

%O 1,1

%A _Benoit Cloitre_, Feb 24 2002

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Last modified October 17 04:09 EDT 2019. Contains 328106 sequences. (Running on oeis4.)