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 A228838 #12 Jul 03 2015 14:43:31 %S A228838 0,6,60,126,120,330,16380,42,4080,7182,3300,1518,32760,78,12180, %T A228838 214830,8160,102,34545420,114,270600,37926,15180,6486,1113840,1650, %U A228838 41340,21546,24360,10266,1703601900,186,16320,2135826,1020,164010,5043631320,222,1140 %N A228838 a(n) = n * A002445(n). %C A228838 a(n+1) is a multiple of A040031(n+1), sequence of period 2: 6, 12. %C A228838 a(n) is divisible by A040879(n)=30 followed by the sequence of period 2: 6, 60. See A040214 and A165734. %C A228838 Note that A164877(n) + A000367(n) = A164558(2n). %H A228838 Colin Barker, <a href="/A228838/b228838.txt">Table of n, a(n) for n = 0..1000</a> %F A228838 a(n) = A176328(2n) - A000367(n). %F A228838 a(n) = A164877(n)/2. %F A228838 a(n+1) = A111008(n) * A036283(n+1). %F A228838 2*a(n) = A164558(2n) - A000367(n). %F A228838 a(n) = A164558(2n) - A176328(2n). %e A228838 a(0)=0*1, a(1)=1*6, a(2)=2*30=60,, a(3)=3*42=126. %o A228838 (PARI) a(n)=n*denominator(bernfrac(2*n)) %K A228838 nonn %O A228838 0,2 %A A228838 _Paul Curtz_, Sep 05 2013 %E A228838 Typo in data fixed by _Colin Barker_, Jul 03 2015