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A320117 Filter sequence for counting the residue classes mod 6 of divisors of n. 6
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 (list; graph; refs; listen; history; text; internal format)
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: A278062 A254597 A064698 * A319996 A319716 A319707

Adjacent sequences:  A320114 A320115 A320116 * A320118 A320119 A320120

KEYWORD

nonn

AUTHOR

Antti Karttunen, Oct 06 2018

STATUS

approved

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Last modified June 21 18:50 EDT 2021. Contains 345365 sequences. (Running on oeis4.)