A320117 Filter sequence for counting the residue classes mod 6 of divisors of n.

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 5, 11, 7, 12, 13, 14, 5, 15, 7, 16, 17, 10, 5, 18, 19, 12, 20, 21, 5, 22, 7, 23, 13, 10, 24, 25, 7, 12, 17, 26, 5, 27, 7, 16, 28, 10, 5, 29, 30, 31, 13, 21, 5, 32, 24, 33, 17, 10, 5, 34, 7, 12, 35, 36, 24, 22, 7, 16, 13, 37, 5, 38, 7, 12, 39, 21, 24, 27, 7, 40, 41, 10, 5, 42, 24, 12, 13, 26, 5, 43, 44, 16, 17, 10, 24, 45, 7, 46, 28, 47, 5, 22, 7, 33

Offset

1,2

Comments

Restricted growth sequence transform of A320116.

For all i, j:

A319717(i) = A319717(j) => a(i) = a(j),

A319996(i) = A319996(j) => a(i) = a(j),

A320113(i) = A320113(j) => a(i) = a(j),

a(i) = a(j) => A002324(i) = A002324(j).

Links

Antti Karttunen, Table of n, a(n) for n = 1..100000

Prog

(PARI)
up_to = 100000;
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; };
A320116(n) = { my(m=1); fordiv(n, d, if(d>1, m *= prime(1+(d%6)))); (m); };
v320117 = rgs_transform(vector(up_to, n, A320116(n)));
A320117(n) = v320117[n];

Crossrefs

Cf. A319717, A319996, A320109, A320113, A320115, A320116.

Sequence in context: A254597 A064698 A373593 * A319996 A319716 A319707

Adjacent sequences: A320114 A320115 A320116 * A320118 A320119 A320120

Keyword

nonn

Author

Antti Karttunen, Oct 06 2018

Status

approved