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 A139108 #5 Oct 03 2015 23:15:22 %S A139108 2,37,2397,153437,157119967,40222711647,2574253545437, %T A139108 2636035630527967,674825121415159677,691020924329123509751, %U A139108 176901356628255618496351,181146989187333753340263903,741978067711319053681720948727 %N A139108 Bisection of A139102. %p A139108 A139101 := proc(n) option remember ; local a,p; if n = 1 then RETURN(1); else a := 10*A139101(n-1) ; for p from ithprime(n-1)+1 to ithprime(n)-1 do a := 10*a+1 ; od: fi ; RETURN(a) ; end: bin2dec := proc(n) local nshft ; nshft := convert(n,base,10) ; add(op(i,nshft)*2^(i-1),i=1..nops(nshft) ) ; end: A139102 := proc(n) bin2dec(A139101(n)) ; end: A139108 := proc(n) A139102(2*n) ; end: seq(A139108(n),n=1..35) ; # _R. J. Mathar_, Apr 25 2008 %Y A139108 Cf. A139102. %K A139108 nonn %O A139108 1,1 %A A139108 _Omar E. Pol_, Apr 08 2008 %E A139108 More terms from _R. J. Mathar_, Apr 25 2008