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A320012 Filter sequence combined from those proper divisors d of n for which 2 == d (mod 3); Restricted growth sequence transform of A319992. 6
1, 1, 1, 2, 1, 2, 1, 2, 1, 3, 1, 2, 1, 2, 4, 5, 1, 2, 1, 3, 1, 6, 1, 5, 4, 2, 1, 7, 1, 3, 1, 5, 8, 9, 4, 2, 1, 2, 1, 10, 1, 7, 1, 6, 4, 11, 1, 5, 1, 3, 12, 13, 1, 2, 14, 15, 1, 16, 1, 17, 1, 2, 1, 18, 4, 6, 1, 9, 19, 20, 1, 5, 1, 2, 4, 21, 8, 13, 1, 10, 1, 22, 1, 7, 23, 2, 24, 25, 1, 3, 1, 11, 1, 26, 4, 18, 1, 7, 8, 27, 1, 9, 1, 28, 29 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

COMMENTS

For all i, j:

  a(i) = a(j) => A320005(i) = A320005(j),

  a(i) = a(j) => A293898(i) = A293898(j).

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..65537

PROG

(PARI)

up_to = 65537;

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; };

A019565(n) = {my(j, v); factorback(Mat(vector(if(n, #n=vecextract(binary(n), "-1..1")), j, [prime(j), n[j]])~))}; \\ From A019565

A319992(n) = { my(m=1); fordiv(n, d, if((d<n)&&(2==(d%3)), m *= A019565(d))); m; };

v320012 = rgs_transform(vector(up_to, n, A319992(n)));

A320012(n) = v320012[n];

CROSSREFS

Cf. A293224, A319992, A320010, A320011, A320013, A320014.

Sequence in context: A060938 A119647 A087942 * A241276 A292286 A099042

Adjacent sequences:  A320009 A320010 A320011 * A320013 A320014 A320015

KEYWORD

nonn

AUTHOR

Antti Karttunen, Oct 03 2018

STATUS

approved

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Last modified February 16 09:23 EST 2019. Contains 320161 sequences. (Running on oeis4.)