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 A278484 #28 Dec 23 2024 14:53:44
%S A278484 0,2,6,12,18,26,38,48,62,78,90,108,132,146,180,206,222,252,288,306,
%T A278484 348,386,398,458,480,528,566,612,648,708,762,806,842,926,948,1008,
%U A278484 1092,1110,1188,1260,1320,1358,1470,1482,1578,1692,1718,1806,1898,1932,2022,2160,2186,2268,2366,2478,2532,2702,2738,2798,2966,3018
%N A278484 Main diagonal of A278482.
%H A278484 Antti Karttunen, <a href="/A278484/b278484.txt">Table of n, a(n) for n = 0..10000</a>
%H A278484 D. Wilson et al., <a href="https://web.archive.org/web/*/http://list.seqfan.eu/oldermail/seqfan/2016-November/thread.html">Interesting sequence</a>, SeqFan list, Nov. 2016
%H A278484 <a href="/index/Si#sieve">Index entries for sequences generated by sieves</a>
%F A278484 By definition, a(n) = A278482(n,n).
%F A278484 a(n) = A000960(n + 1) - 1.
%F A278484 a(n) = 2*A073359(n). [Observed by _Arie Groeneveld_ on SeqFan list, Nov 22 2016.] [Conjectural, true for n <= 2000 _David W. Wilson_, Nov 23 2016]
%t A278484 a[n_]:= Fold[Floor@Times@##&,Prepend[Table[(k + 1)/k, {k, n, 1, -1}], n]] (* _Ethan Beihl_, Nov 29 2016 *)
%Y A278484 Cf. A000960, A073359.
%Y A278484 Main diagonal of A278482 (and A278483).
%Y A278484 Partial sums of A278484.
%K A278484 nonn
%O A278484 0,2
%A A278484 _Antti Karttunen_, Nov 23 2016 after _David W. Wilson_'s posting on SeqFan list Nov 22 2016