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A319999 Filter sequence combining A173557(n) with A319993(n). 2
1, 2, 3, 4, 5, 6, 7, 4, 8, 9, 10, 11, 12, 13, 14, 4, 15, 16, 17, 18, 12, 19, 20, 11, 21, 22, 23, 24, 25, 26, 27, 4, 28, 29, 30, 11, 31, 32, 30, 18, 33, 22, 34, 35, 36, 37, 38, 11, 39, 40, 41, 42, 43, 44, 33, 24, 31, 45, 46, 47, 48, 49, 50, 4, 51, 52, 53, 54, 55, 56, 57, 11, 58, 59, 60, 61, 48, 56, 62, 18, 63, 64, 65, 42, 66, 67, 68, 35, 69, 70, 58, 71, 48, 72, 58, 11, 73, 74, 75, 18, 76, 77, 78, 42 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Restricted growth sequence transform of ordered pair [A173557(n), A319993(n)].

For all i, j: a(i) = a(j) => A319997(i) = A319997(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; };

A173557(n) = factorback(apply(p -> p-1, factor(n)[, 1]));

A319993(n) =  { my(f=factor(n)); prod(i=1, #f~, if(2==f[i, 1], -(1==f[i, 2]), (f[i, 1]^(f[i, 2]-1)))); };

v319999 = rgs_transform(vector(up_to, n, [A173557(n), A319993(n)]));

A319999(n) = v319999[n];

CROSSREFS

Cf. A173557, A319993, A319997.

Cf. also A295886, A295887.

Sequence in context: A038388 A272573 A328477 * A083501 A007922 A007948

Adjacent sequences:  A319996 A319997 A319998 * A320000 A320001 A320002

KEYWORD

nonn

AUTHOR

Antti Karttunen, Nov 08 2018

STATUS

approved

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Last modified December 14 22:42 EST 2019. Contains 329987 sequences. (Running on oeis4.)