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Let q(p) be the smallest prime greater than the prime p. a(n) is the smallest integer > n that is divisible by each q(p) for all primes p dividing n.
1

%I #11 Apr 05 2022 10:28:08

%S 3,5,6,7,15,11,9,10,21,13,15,17,33,35,18,19,30,23,21,55,39,29,30,28,

%T 51,30,33,31,105,37,33,65,57,77,45,41,69,85,42,43,165,47,78,70,87,53,

%U 60,55,63,95,102,59,60,91,66,115,93,61,105,67,111,110,66,119,195,71,114,145

%N Let q(p) be the smallest prime greater than the prime p. a(n) is the smallest integer > n that is divisible by each q(p) for all primes p dividing n.

%H Harvey P. Dale, <a href="/A163620/b163620.txt">Table of n, a(n) for n = 2..1000</a>

%e 18 is divisible by 2 and 3. q(2) = 3, and q(3) = 5. So a(18) is the smallest integer > 18 that is divisible by both 3 and 5. Therefore a(18) = 30.

%t spf[n_]:=Module[{prs=NextPrime/@FactorInteger[n][[All,1]],p,k=1},p= LCM@@ prs;While[ k*p<n,k++];k*p]; Array[spf,70,2]

%K nonn

%O 2,1

%A _Leroy Quet_, Aug 01 2009

%E Correct second term and extend sequence _Sean A. Irvine_, Sep 06 2009