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 A020646 #18 Jun 29 2017 11:39:33
%S A020646 1,7,14,21,28,35,42,49,49,56,63,70,77,84,91,98,98,105,112,119,126,133,
%T A020646 140,147,147,154,161,168,175,182,189,196,196,203,210,217,224,231,238,
%U A020646 245,245,252,259,266,273,280,287,294,294,301,308,315,322,329,336,343,343,343,350
%N A020646 Least positive integer k for which 7^n divides k!.
%D A020646 H. Ibstedt, Smarandache Primitive Numbers, Smarandache Notions Journal, Vol. 8, No. 1-2-3, 1997, 216-229.
%H A020646 T. D. Noe, <a href="/A020646/b020646.txt">Table of n, a(n) for n = 0..1000</a>
%H A020646 F. Smarandache, <a href="http://www.gallup.unm.edu/~smarandache/OPNS.pdf">Only Problems, Not Solutions!</a>
%t A020646 lpi[n_]:=Module[{k = 1, n7 = 7^n}, While[! Divisible[k!, n7], k++]; k]; Array[lpi,60,0] (* _Harvey P. Dale_, Jun 29 2017 *)
%o A020646 (PARI) a(n) = {k = 1; while (valuation(k!, 7) < n, k++); k;} \\ _Michel Marcus_, Aug 19 2013
%Y A020646 Cf. A007843, A007844, A007845.
%K A020646 nonn
%O A020646 0,2
%A A020646 _David W. Wilson_