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A327936 Multiplicative with a(p^e) = p if e >= p, otherwise 1. 6
1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 3, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 3, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 3, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 6, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

LINKS

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

FORMULA

Multiplicative with a(p^e) = p if e >= p, otherwise 1.

A001221(a(n)) = A129251(n).

EXAMPLE

For n = 12 = 2^2 * 3^1, only prime factor p = 2 satisfies p^p | 12, thus a(12) = 2.

For n = 108 = 2^2 * 3^3, both prime factors p = 2 and p = 3 satisfy p^p | 108, thus a(108) = 2*3 = 6.

MATHEMATICA

Array[Apply[Times, FactorInteger[#] /. {p_, e_} /; IntegerQ@ p :> If[e >= p, p, 1]] &, 120] (* Michael De Vlieger, Oct 01 2019 *)

PROG

(PARI) A327936(n) = { my(f = factor(n)); for(k=1, #f~, f[k, 2] = (f[k, 2]>=f[k, 1])); factorback(f); };

CROSSREFS

Cf. A001221, A129251, A327937, A327938, A327939.

Differs from A129252 for the first time at n=108.

Sequence in context: A268238 A081117 A129252 * A022929 A307706 A161102

Adjacent sequences:  A327933 A327934 A327935 * A327937 A327938 A327939

KEYWORD

nonn,mult

AUTHOR

Antti Karttunen, Oct 01 2019

STATUS

approved

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Last modified December 10 20:53 EST 2019. Contains 329909 sequences. (Running on oeis4.)