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Least m with n*(n+1)/2 divisors.
2

%I #13 Apr 09 2024 03:25:03

%S 1,4,12,48,144,576,960,1260,3600,82944,46080,184320,2985984,129600,

%T 55440,6881280,14745600,58982400,106168320,907200,18662400,

%U 247669456896,1321205760,2494800,207360000,45158400,7761600,978447237120,543581798400,2174327193600,1014686023680

%N Least m with n*(n+1)/2 divisors.

%H Amiram Eldar, <a href="/A081620/b081620.txt">Table of n, a(n) for n = 1..1000</a>

%F A000005(a(n)) = A000217(n) and A000005(k) <> n*(n+1)/2 for k < a(n).

%F a(n) = A005179(A000217(n)) = A005179(n*(n+1)/2).

%Y Subsequence of A081619.

%Y Cf. A000005, A000217, A005179.

%K nonn

%O 1,2

%A _Reinhard Zumkeller_, Mar 24 2003

%E More terms from _David Wasserman_, Jun 14 2004

%E a(29)-a(31) from _Amiram Eldar_, Apr 09 2024