cp's OEIS Frontend

A292259 Restricted growth sequence transform of A292258; filter constructed from the prime signatures of the sequence [n, floor(n/2), floor(n/4), ..., 1].

%I A292259 #7 Sep 23 2017 19:13:21
%S A292259 1,2,2,3,4,5,4,6,7,8,9,10,8,8,8,11,12,13,14,15,16,17,18,19,20,16,21,
%T A292259 15,17,22,17,23,24,25,25,26,27,28,28,29,30,31,32,30,30,33,34,35,36,37,
%U A292259 38,39,32,40,41,29,39,32,33,42,43,32,30,44,45,46,47,48,49,50,51,52,53,54,55,54,56,57,58,59,60,61,62,63,64,65,65,66,62,67,61,62
%N A292259 Restricted growth sequence transform of A292258; filter constructed from the prime signatures of the sequence [n, floor(n/2), floor(n/4), ..., 1].
%H A292259 Antti Karttunen, <a href="/A292259/b292259.txt">Table of n, a(n) for n = 1..65535</a>
%o A292259 (PARI)
%o A292259 up_to = 65535
%o A292259 rgs_transform(invec) = { my(om = Map(), outvec = vector(length(invec)), u=1); for(i=1, length(invec), if(mapisdefined(om,invec[i]), my(pp = mapget(om, invec[i])); outvec[i] = outvec[pp] , mapput(om,invec[i],i); outvec[i] = u; u++ )); outvec; };
%o A292259 write_to_bfile(start_offset,vec,bfilename) = { for(n=1, length(vec), write(bfilename, (n+start_offset)-1, " ", vec[n])); }
%o A292259 A046523(n) = { my(f=vecsort(factor(n)[, 2], , 4), p); prod(i=1, #f, (p=nextprime(p+1))^f[i]); };  \\ This function from _Charles R Greathouse IV_, Aug 17 2011
%o A292259 v101296 = rgs_transform(vector(up_to, n, A046523(n)));
%o A292259 A101296(n) = v101296[n];
%o A292259 A292258(n) = if(1==n,n,prime(A101296(n)-1) * A292258(n\2));
%o A292259 write_to_bfile(1,rgs_transform(vector(up_to,n,A292258(n))),"b292259.txt");
%Y A292259 Cf. A292258.
%Y A292259 Cf. A078349 (one of the matching sequences).
%K A292259 nonn
%O A292259 1,2
%A A292259 _Antti Karttunen_, Sep 22 2017