A293224 Restricted growth sequence transform of A293222, a product formed from the 2-digits present in the ternary expansions of proper divisors of n.

1, 1, 1, 2, 1, 2, 1, 2, 1, 3, 1, 4, 1, 4, 2, 5, 1, 4, 1, 3, 6, 3, 1, 7, 2, 2, 1, 5, 1, 7, 1, 7, 2, 5, 4, 8, 1, 9, 1, 10, 1, 11, 1, 12, 4, 12, 1, 13, 6, 14, 4, 14, 1, 8, 3, 15, 16, 3, 1, 17, 1, 2, 18, 15, 2, 11, 1, 7, 9, 19, 1, 20, 1, 2, 21, 12, 4, 11, 1, 22, 1, 3, 1, 23, 5, 4, 2, 22, 1, 24, 6, 25, 1, 12, 9, 26, 1, 14, 4, 27, 1, 13, 1, 28, 23, 14, 1, 29, 1, 30

Offset

1,4

Links

Antti Karttunen, Table of n, a(n) for n = 1..19683

Prog

(PARI)
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; };
write_to_bfile(start_offset, vec, bfilename) = { for(n=1, length(vec), write(bfilename, (n+start_offset)-1, " ", vec[n])); }
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
A289814(n) = { my (d=digits(n, 3)); fromdigits(vector(#d, i, if (d[i]==2, 1, 0)), 2); } \\ From _Remy Sigrist_
A293222(n) = { my(m=1); fordiv(n, d, if(d < n, m *= A019565(A289814(d)))); m; };
write_to_bfile(1, rgs_transform(vector(19683, n, A293222(n))), "b293224.txt");

Crossrefs

Cf. A293222.

Cf. also A290092, A293223, A293215, A293217, A293232, A293225, A293226.

Sequence in context: A369916 A085342 A025825 * A082303 A316384 A029838

Adjacent sequences: A293221 A293222 A293223 * A293225 A293226 A293227

Keyword

nonn

Author

Antti Karttunen, Oct 03 2017

Status

approved