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 A085211 #12 May 18 2024 14:56:09 %S A085211 0,1,1,2,3,2,3,6,6,3,4,7,12,7,4,5,12,14,14,12,5,6,11,24,15,24,13,6,7, %T A085211 14,22,28,28,26,14,7,8,15,28,23,48,29,28,15,8,9,24,30,30,44,52,30,30, %U A085211 24,9,10,19,48,31,56,45,56,31,48,25,10,11,22,38,56,60,58,46,60,56,50,26,11 %N A085211 Array A(x,y): concatenation of the binary expansions of x & y in such a way that 'y' is inserted after the least significant 1-bit of 'x', followed by the remaining 0-bits, if any. Listed antidiagonalwise as A(0,0), A(1,0), A(0,1), A(2,0), A(1,1), A(0,2), ... Zero is expanded as an empty string. %F A085211 a(0, y) = y, a(x, y) = A006519(x) * (y + ((2^A029837(y+1))*A000265(x))). %e A085211 A(8,3) = 56 = '1110000' in binary, is produced when '11' (binary expansion of 3) is inserted after the least significant (and only) 1-bit of '1000' (binary expansion of 8). %o A085211 (MIT/GNU Scheme) (define (A085211bi x y) (cond ((zero? x) (A085207bi x y)) (else (* (+ (* (expt 2 (A029837 (1+ y))) (A000265 x)) y) (A006519 x))))) %o A085211 (define (A085211 n) (A085211bi (A025581 n) (A002262 n))) %o A085211 (define (A085212 n) (A085211bi (A002262 n) (A025581 n))) %Y A085211 Same array in binary: A085213. Transpose: A085212. Variant: A085207 (normal concatenation). Can be used to compute A085203. %K A085211 nonn,tabl %O A085211 0,4 %A A085211 _Antti Karttunen_, Jun 23 2003