A318892 - OEIS

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A318892

Filter sequence combining the prime signature of n (A046523) with A289625.

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 35, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 44, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 68, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 75, 90

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OFFSET

1,2

COMMENTS

Restricted growth sequence transform of A289628.

For all i, j: a(i) = a(j) => A318893(i) = A318893(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; };

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

A289625(n) = { my(m=1, p=2, v=znstar(n)[2]); for(i=1, length(v), m *= p^v[i]; p = nextprime(p+1)); (m); };

A318892aux(n) = [A046523(n), A289625(n)];

v318892 = rgs_transform(vector(up_to, n, A318892aux(n)));

A318892(n) = v318892[n];

CROSSREFS

Cf. A046523, A289625, A289628, A318839, A318893.

Sequence in context: A188462 A352530 A058321 * A323404 A056064 A274055

Adjacent sequences: A318889 A318890 A318891 * A318893 A318894 A318895

KEYWORD

nonn

AUTHOR

Antti Karttunen, Sep 16 2018

STATUS

approved