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 A106446 #7 Mar 31 2012 14:02:21 %S A106446 0,1,2,3,4,7,6,11,8,5,14,25,12,19,22,9,16,47,10,31,28,29,50,13,24,21, %T A106446 38,15,44,61,18,137,128,43,94,49,20,55,62,53,56,97,58,115,100,27,26, %U A106446 37,48,69,42,113,76,73,30,79,88,33,122,319,36,41,274,39,64,121,86,185 %N A106446 Doubly-recursed cross-domain bijection from N to GF(2)[X]. Variant of A091204 and A106444. %C A106446 Differs from A091204 for the first time at n=32, where A091204(32)=32, while a(32)=128. Differs from A106444 for the first time at n=11, where A106444(11)=13, while a(11)=25. %H A106446 A. Karttunen, <a href="/A091247/a091247.scm.txt">Scheme-program for computing this sequence.</a> %H A106446 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a> %F A106446 a(0)=0, a(1)=1, a(p_i) = A014580(a(i)) for primes p_i with index i and for composites n = p_i^e_i * p_j^e_j * p_k^e_k * ..., a(n) = A048723(a(p_i), a(e_i)) X A048723(a(p_j), a(e_j)) X A048723(a(p_k), a(e_k)) X ..., where X stands for carryless multiplication of GF(2)[X] polynomials (A048720) and A048723(n, y) raises the n-th GF(2)[X] polynomial to the y:th power. %e A106446 a(5) = 7, as 5 is the 3rd prime, a(3)=3 and the third irreducible GF(2)[X] polynomial x^2+x+1 is encoded as A014580(3) = 7. a(11) = 25, as 11 is the 5th prime, a(5)=7 and the seventh irreducible GF(2)[X] polynomial x^4+x^3+1 is encoded as A014580(7) = 25. a(32) = a(2^5) = A048723(a(2),a(5)) = A048723(2,7) = 128. %Y A106446 Inverse: A106447. Variant: A091204. %K A106446 nonn %O A106446 0,3 %A A106446 _Antti Karttunen_, May 09 2005