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 A167502 #3 Jul 14 2012 11:32:32 %S A167502 1,10,100,111,1000,1001,1010,1110,10001,10010,10100,10110,10111,11000, %T A167502 11010,11110,11111,100010,100100,100110,101001,101011,101100,101110, %U A167502 110000,110001,110010,110011,110100,111000,111001,111011,111101,111110 %N A167502 Sequence A167500 (= list of nonzero bits in this sequence), written in binary. %F A167502 A167502 = A007088 o A167500 %e A167502 Sequence A167500 starts 1,2,4,7,... = 1,10,100,111,.... when written in binary. %o A167502 (PARI) a=b=[]; for(n=1,30, #b >= n & for( i=a[n-1]+1,#b, b[i] & (a=concat(a,i)) & break); #a<n & a=concat(a,#b+1); b=concat(b,binary( a[n] ))); apply(t->subst(Pol(binary(t)),x,10),a) %Y A167502 Cf. A167500 (this sequence written in decimal), A167501 (the digits of this sequence). %K A167502 base,nonn %O A167502 1,2 %A A167502 _M. F. Hasler_, Nov 05 2009