This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A099795 #21 Oct 25 2024 09:35:24
%S A099795 1,2,12,60,2520,27720,720720,12252240,232792560,80313433200,
%T A099795 2329089562800,144403552893600,5342931457063200,219060189739591200,
%U A099795 9419588158802421600,3099044504245996706400,164249358725037825439200,9690712164777231700912800
%N A099795 Least common multiple of 1, 2, 3, ..., prime(n)-1.
%C A099795 Alternative definition: a(n) = Product{i = 1..(n-1)}prime(i)^e_i, where prime(i)^e_i is the greatest power of prime(i) which does not exceed prime(n). Every term is a product of prime powers, and also of primorial powers(the greatest of which is A002110(n-1); see Example and A053589). - _David James Sycamore_, Oct 24 2024
%H A099795 Robert Israel, <a href="/A099795/b099795.txt">Table of n, a(n) for n = 1..342</a>
%F A099795 a(n) = (A094998(n)-1) / A099796(n).
%F A099795 a(n) = A038610(A000040(n)). - _Anthony Browne_, Jul 19 2016
%F A099795 Rad(a(n)) = A007947(a(n)) = A002110(n-1). - _David James Sycamore_, Oct 24 2024
%e A099795 For n = 7, prime(7) = 17, using the alternative definition (see Comment), a(7) = 2^4*3^2*5^1*7^1*11^1*13^1 = 16*9*5*7*11*13 = 720720 = 24*30030 = 2^2*6*30030 = A002110(1)^2*A002110(2)*A002110(6). - _David James Sycamore_, Oct 24 2024
%p A099795 Primes:= select(isprime, [2,$3..100]):
%p A099795 seq(ilcm($2..Primes[i]-1),i=1..nops(Primes)); # _Robert Israel_, Jul 19 2016
%t A099795 LCM@@Range[#]&/@(Prime[Range[20]]-1) (* _Harvey P. Dale_, Jan 30 2015 *)
%o A099795 (Magma) [Lcm([2..p-1]): p in PrimesUpTo(70)]; // _Bruno Berselli_, Feb 06 2015
%Y A099795 Cf. A094998, A099794, A099796, A038610, A000040.
%Y A099795 Cf. A002110, A007947, A053589.
%K A099795 nonn
%O A099795 1,2
%A A099795 _Ray Chandler_, Oct 29 2004
%E A099795 a(18) from _Bruno Berselli_, Feb 06 2015