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A293223 Restricted growth sequence transform of A293221, a product formed from the 1-digits present in the ternary expansion of proper divisors of n.

%I A293223 #7 Oct 18 2017 00:56:12
%S A293223 1,2,2,2,2,3,2,4,3,3,2,5,2,6,7,4,2,8,2,9,4,10,2,11,3,12,8,9,2,13,2,14,
%T A293223 8,10,4,15,2,6,16,9,2,11,2,9,17,3,2,18,6,14,8,9,2,19,8,20,4,21,2,22,2,
%U A293223 23,16,24,16,25,2,26,7,27,2,28,2,29,16,26,30,31,2,32,19,19,2,33,8,29,34,27,2,35,14,36,37,21,4,38,2,24,39,40,2,41,2,20,42
%N A293223 Restricted growth sequence transform of A293221, a product formed from the 1-digits present in the ternary expansion of proper divisors of n.
%H A293223 Antti Karttunen, <a href="/A293223/b293223.txt">Table of n, a(n) for n = 1..19683</a>
%o A293223 (PARI)
%o A293223 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 A293223 write_to_bfile(start_offset,vec,bfilename) = { for(n=1, length(vec), write(bfilename, (n+start_offset)-1, " ", vec[n])); }
%o A293223 A019565(n) = {my(j,v); factorback(Mat(vector(if(n, #n=vecextract(binary(n), "-1..1")), j, [prime(j), n[j]])~))}; \\ This function from _M. F. Hasler_
%o A293223 A289813(n) = { my (d=digits(n, 3)); fromdigits(vector(#d, i, if (d[i]==1, 1, 0)), 2); } \\ From _Remy Sigrist_
%o A293223 A293221(n) = { my(m=1); fordiv(n,d,if(d < n,m *= A019565(A289813(d)))); m; };
%o A293223 write_to_bfile(1,rgs_transform(vector(19683,n,A293221(n))),"b293223.txt");
%Y A293223 Cf. A293221.
%Y A293223 Cf. also A290091, A293224, A293225, A293226, A293215, A293217, A293232.
%K A293223 nonn
%O A293223 1,2
%A A293223 _Antti Karttunen_, Oct 03 2017