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 A120230 #14 Mar 05 2020 10:56:25 %S A120230 4,8,12,1,20,24,28,2,36,40,44,3,52,56,60,64,68,72,76,5,84,88,92,6,100, %T A120230 104,108,7,116,120,124,128,132,136,140,9,148,152,156,10,164,168,172, %U A120230 11,180,184,188,192,196,200,204,13,212,216,220,14,228,232,236,15,244,248 %N A120230 Split-floor-multiplier sequence (SFMS) using multipliers 1/4 and 4. (SFMS is defined at A120229.) %C A120230 Self-inverse permutation of the natural numbers. %H A120230 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a> %F A120230 a(n)=[n/4] if this is positive and new, else a(n)=4n. %e A120230 a(1)=1*4 because [1/4] is not positive. %e A120230 a(2)=2*4 because [2/4] is not positive. %e A120230 a(3)=3*4 because [3/4] is not positive. %e A120230 a(4)=1=[4*(1/4)]. %e A120230 a(5)=5*4 because [5/4]=a(4), not new. %Y A120230 Cf. A073675, A120229, A120230. %Y A120230 Row 4 and column 4 of A059897. %K A120230 nonn %O A120230 1,1 %A A120230 _Clark Kimberling_, Jun 11 2006