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 A061799 #43 Jan 01 2022 09:55:28 %S A061799 1,2,4,6,12,12,24,24,36,48,60,60,120,120,120,120,180,180,240,240,360, %T A061799 360,360,360,720,720,720,720,720,720,840,840,1260,1260,1260,1260,1680, %U A061799 1680,1680,1680,2520,2520,2520,2520,2520,2520,2520,2520,5040,5040,5040 %N A061799 Smallest number with at least n divisors. %C A061799 Smallest number which can be expressed as the least common multiple of n distinct numbers. - _Amarnath Murthy_, Nov 27 2002 %C A061799 Also smallest possible member of a set of n+1 numbers with pairwise distinct GCD's. [Following an observation by _Charles R Greathouse IV_] (Proof: If the smallest number min(S) of the set (with card(S)=n+1) has a distinct GCD with each of the other n numbers, then it must have at least n distinct divisors (because any GCD is a divisor). It is then easy to choose larger members of the set so that all pairs of elements have pairwise distinct GCD's, e.g., by successively multiplying by distinct and sufficiently large primes.) - _M. F. Hasler_, Mar 05 2013 %H A061799 Amiram Eldar, <a href="/A061799/b061799.txt">Table of n, a(n) for n = 1..10000</a> (terms 1..2000 from T. D. Noe) %e A061799 a(5)=12 since every number less than 12 has fewer than five divisors (1 has one; 2,3,5,7 and 11 have two each; 4 and 9 have three each; 6,8 and 10 have four each) while 12 has at least five (in fact it has six: 1,2,3,4,6 and 12). %t A061799 Reap[ For[ n = 1, n <= 100, n++, s = n; While[ DivisorSigma[0, s] < n, s++]; Sow[s] ] ][[2, 1]] (* _Jean-François Alcover_, Feb 16 2012, after Pari *) %t A061799 With[{ds=Table[{n,DivisorSigma[0,n]},{n,6000}]},Table[SelectFirst[ds,#[[2]] >= k&],{k,60}]][[All,1]] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Dec 15 2019 *) %o A061799 (PARI) for(n=1,100,s=n; while(numdiv(s)<n,s++); print1(s,",")) %o A061799 (Haskell) %o A061799 import Data.List (findIndex) %o A061799 import Data.Maybe (fromJust) %o A061799 a061799 n = succ $ fromJust $ findIndex (n <=) $ map a000005 [1..] %o A061799 -- _Reinhard Zumkeller_, Apr 01 2011 %Y A061799 Cf. A000005, A002182, A002183, A005179, A213918. %K A061799 nice,nonn %O A061799 1,2 %A A061799 _Henry Bottomley_, Jun 22 2001 %E A061799 Replaced "factors" by "divisors" in definition and example _M. F. Hasler_, Oct 24 2010