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 A270875 #19 May 03 2020 02:02:25
%S A270875 0,0,1,1,1,2,2,3,5,6,6,9,9,10,13,15,15,19,19,33,35,35,35,47,47,47,50,
%T A270875 57,57,101,101,106,108,108,108,127,127,127,128,249,249,268,268,272,
%U A270875 358,358,358,406,406,408,409,411,411,424,424,501,502,502,502,1190,1190
%N A270875 Number of subsets of {1,...,n} with sum of elements equal to least common multiple of elements and at least two elements.
%C A270875 It appears that the sequence of n for which a(n)>a(n-1) has a large overlap with A175904.
%F A270875 a(n) = A270970(n) - n. - _Michel Marcus_, Mar 27 2016
%e A270875 For n=3, the subsets of {1,2,3} with at least two elements have (sum,LCM) as follows: {1,2}->(3,2), {1,3}->(4,3), {2,3}->(5,6), {1,2,3}->(6,6). Only the last satisfies sum=LCM, so a(3)=1.
%t A270875 Table[Length[Transpose@ {Total /@ #, LCM @@@ #} /. {a_, b_} /; a != b -> Nothing &@ Rest[Subsets[Range@ n] /. {_} -> Nothing]], {n, 2, 22}] (* _Michael De Vlieger_, Mar 24 2016 *)
%o A270875 (PARI) a(n) = {nb = 0; S = vector(n, k, k); for (i = 0, 2^n - 1, ss = vecextract(S, i); if (vecsum(ss) == lcm(ss), nb++);); nb - n;} \\ _Michel Marcus_, Mar 26 2016
%Y A270875 Cf. A270970 (similar sequence counting trivial solutions).
%K A270875 nonn
%O A270875 1,6
%A A270875 _Logan J. Kleinwaks_, Mar 24 2016
%E A270875 More terms added using A270970 by _Jinyuan Wang_, May 02 2020