A302854 - OEIS

%I #6 Jun 07 2018 22:07:25

%S 0,1,3,2,5,25,4,26,7,8,10,9,6,28,11,27,13,14,16,15,18,30,17,31,20,21,

%T 23,22,19,29,12,24,65,66,7483,7484,70,90,7488,7508,68,67,7486,7485,69,

%U 91,7487,7509,72,73,7490,7491,71,93,7489,7511,75,74,7493,7492,76,92,7494,7510,33,34,36,35,38,58,37,59,40,41,43,42,39

%N Inverse of A302853: if A302853(k) = n, a(n) = k, or -1 if n does not occur in A302853.

%C This is a left inverse of A302853, and also the right inverse if A282291 (and thus also A302853) is surjective (a permutation of natural numbers), in which case the fallback-clause is unnecessary.

%H Antti Karttunen, <a href="/A302854/b302854.txt">Table of n, a(n) for n = 0..259</a>

%F For all n >= 0, a(A302853(n)) = n.

%o (PARI)

%o \\ For other needed code, follow A050376 and A282291:

%o A052330(n) = { my(p=1, i=1); while(n>0, if(n%2, p *= A050376(i)); i++; n >>= 1); (p); };

%o A302854(n) = (A304090(A052330(n))-1);

%Y Cf. A302853 (inverse).

%K nonn

%O 0,3

%A _Antti Karttunen_, May 17 2018