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 A169825 #17 Apr 17 2024 03:40:54 %S A169825 0,420,840,1260,1680,2100,2520,2940,3360,3780,4200,4620,5040,5460, %T A169825 5880,6300,6720,7140,7560,7980,8400,8820,9240,9660,10080,10500,10920, %U A169825 11340,11760,12180,12600,13020,13440,13860,14280,14700,15120,15540,15960,16380,16800 %N A169825 Multiples of 420. %C A169825 Numbers that are divisible by all of 1,2,3,4,5,6,7. %H A169825 Erich Friedman, <a href="https://erich-friedman.github.io/numbers.html">What's Special About This Number?</a> (See the entry for "420") %H A169825 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (2,-1). %F A169825 a(n) = 420*n. - _Wesley Ivan Hurt_, Apr 11 2021 %F A169825 From _Elmo R. Oliveira_, Apr 16 2024: (Start) %F A169825 G.f.: 420*x/(x-1)^2. %F A169825 E.g.f.: 420*x*exp(x). %F A169825 a(n) = 2*a(n-1) - a(n-2) for n >= 2. %F A169825 a(n) = 7*A169823(n) = 14*A249674(n) = 15*A135628(n) = 20*A008603(n) = 21*A008602(n) = 28*A008597(n) = 30*A008596(n) = 60*A008589(n) = 420*A001477(n) = A169827(n)/2. (End) %t A169825 Range[0, 100]*420 (* _Paolo Xausa_, Apr 17 2024 *) %o A169825 (PARI) a(n)=420*n \\ _Charles R Greathouse IV_, Apr 16 2024 %Y A169825 Cf. A001477, A008589, A008596, A008597, A008602, A008603. %Y A169825 Cf. A135628, A169823, A169827, A249674. %K A169825 nonn,easy %O A169825 0,2 %A A169825 _N. J. A. Sloane_, May 30 2010