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 A037280 #12 Sep 04 2017 04:08:46 %S A037280 1,1,3,1,5,23,7,3,3,25,11,1173,13,27,35,31,17,2369,19,12255,37,211,23, %T A037280 586703,5,213,39,12357,29,23561015,31,1551,311,217,57,117345609,37, %U A037280 219,313,6145255,41,23671421,43,120561,35915,223,47,2933515203,7,251025,317 %N A037280 If n is composite replace n with the concatenation of its nontrivial divisors [ A037279 ] then divide out any factors of 2. %e A037280 Divisors of 12 are 1,2,3,4,6,12, so 12 -> 2346 = 2*1173 -> 1173 = a(12). %p A037280 with(numtheory):ds:=proc(s) local j: RETURN(add(s[j]*10^(j-1),j=1..nops(s))):end: a:=proc(n) options remember: local d,i,l,m: if n<3 then RETURN(1) else if not isprime(n) then d:=divisors(n): l:=nops(d): m:=ds([seq(op(convert(d[l-i+1],base,10)),i=2..l-1)]): RETURN(m/piecewise(m mod 2=1,1,2^(ifactors(m)[2][1][2]))) else RETURN(n) fi fi: end; seq(a(n),n=1..70); # C. Ronaldo %Y A037280 Cf. A037279. %K A037280 nonn,easy,base %O A037280 1,3 %A A037280 _N. J. A. Sloane_ %E A037280 More terms from _Erich Friedman_