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A305893 Filter sequence combining 3-adic valuation (A007949) and the prime signature (A046523) of n. 3
1, 2, 3, 4, 2, 5, 2, 6, 7, 8, 2, 9, 2, 8, 5, 10, 2, 11, 2, 12, 5, 8, 2, 13, 4, 8, 14, 12, 2, 15, 2, 16, 5, 8, 8, 17, 2, 8, 5, 18, 2, 15, 2, 12, 11, 8, 2, 19, 4, 12, 5, 12, 2, 20, 8, 18, 5, 8, 2, 21, 2, 8, 11, 22, 8, 15, 2, 12, 5, 23, 2, 24, 2, 8, 9, 12, 8, 15, 2, 25, 26, 8, 2, 21, 8, 8, 5, 18, 2, 27, 8, 12, 5, 8, 8, 28, 2, 12, 11, 29, 2, 15, 2, 18, 15 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Restricted growth sequence transform of A286463, of the ordered pair [A007949(n), A046523(n)].

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; };

A007949(n) = valuation(n, 3);

A046523(n) = { my(f=vecsort(factor(n)[, 2], , 4), p); prod(i=1, #f, (p=nextprime(p+1))^f[i]); };  \\ From A046523

Aux305893(n) = [A007949(n), A046523(n)];

v305893 = rgs_transform(vector(up_to, n, Aux305893(n)));

A305893(n) = v305893[n];

CROSSREFS

Cf. A007949, A046523, A286463, A305900.

Cf. also A305891.

Sequence in context: A191248 A323156 A075994 * A325980 A182718 A212645

Adjacent sequences:  A305890 A305891 A305892 * A305894 A305895 A305896

KEYWORD

nonn

AUTHOR

Antti Karttunen, Jun 14 2018

STATUS

approved

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Last modified October 14 02:29 EDT 2019. Contains 327995 sequences. (Running on oeis4.)