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 A259987 #13 Jul 18 2015 14:53:30 %S A259987 4,28,136,1216,1216,16768,203392,1043200,6082048,36315136,36315136, %T A259987 1487503360,1487503360,1487503360,314944159744,785129144320, %U A259987 12069568774144,45922887663616,452162714337280,2280241934368768,2280241934368768,2280241934368768,2280241934368768 %N A259987 This sequence and A259986 are base 6 analogs of A007185 and A016090, written in base 10. %C A259987 See Schut (1991) for precise definition. %C A259987 Ignoring repetitions, the subsequence of A237583 of terms ending in 4 in base 6. - _Eric M. Schmidt_, Jul 18 2015 %D A259987 C. P. Schut, Idempotents. Report AM-R9101, Centrum voor Wiskunde en Informatica, Amsterdam, 1991. %H A259987 Eric M. Schmidt, <a href="/A259987/b259987.txt">Table of n, a(n) for n = 1..1000</a> %o A259987 (Sage) def a(n) : return crt(0, 1, 2^n, 3^n) # _Eric M. Schmidt_, Jul 18 2015 %Y A259987 Cf. A007185, A016090, A201821, A237583, A259986-A259991. %K A259987 nonn,base %O A259987 1,1 %A A259987 _N. J. A. Sloane_, Jul 13 2015 %E A259987 More terms from _Eric M. Schmidt_, Jul 18 2015