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A331178 Number of values of k, 1 <= k <= n, with A023900(k) = A023900(n), where A023900 is Dirichlet inverse of Euler totient function phi. 3
1, 1, 1, 2, 1, 1, 1, 3, 2, 1, 1, 2, 1, 1, 1, 4, 1, 3, 1, 2, 1, 1, 1, 4, 2, 2, 3, 2, 1, 1, 1, 5, 1, 1, 1, 5, 1, 1, 2, 3, 1, 2, 1, 2, 2, 1, 1, 6, 2, 4, 1, 3, 1, 7, 1, 3, 1, 1, 1, 2, 1, 1, 4, 6, 1, 1, 1, 2, 1, 1, 1, 8, 1, 2, 3, 2, 1, 2, 1, 5, 4, 2, 1, 3, 1, 1, 1, 3, 1, 3, 1, 2, 2, 1, 2, 9, 1, 4, 2, 6, 1, 1, 1, 5, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

COMMENTS

Ordinal transform of A023900.

LINKS

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

PROG

(PARI)

up_to = 65537;

ordinal_transform(invec) = { my(om = Map(), outvec = vector(length(invec)), pt); for(i=1, length(invec), if(mapisdefined(om, invec[i]), pt = mapget(om, invec[i]), pt = 0); outvec[i] = (1+pt); mapput(om, invec[i], (1+pt))); outvec; };

A023900(n) = factorback(apply(p -> 1-p, factor(n)[, 1]));

v331178 = ordinal_transform(vector(up_to, n, A023900(n)));

A331178(n) = v331178[n];

CROSSREFS

Cf. A000010, A023900.

Cf. also A081373, A331175, A331179, A331180.

Sequence in context: A322885 A292582 A008479 * A227350 A107345 A336736

Adjacent sequences:  A331175 A331176 A331177 * A331179 A331180 A331181

KEYWORD

nonn

AUTHOR

Antti Karttunen, Jan 11 2020

STATUS

approved

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Last modified October 26 08:06 EDT 2020. Contains 338027 sequences. (Running on oeis4.)