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A292269 If n is 1 or a prime, then a(n) = 1, otherwise a(n) = the third smallest divisor of n. 7
1, 1, 1, 4, 1, 3, 1, 4, 9, 5, 1, 3, 1, 7, 5, 4, 1, 3, 1, 4, 7, 11, 1, 3, 25, 13, 9, 4, 1, 3, 1, 4, 11, 17, 7, 3, 1, 19, 13, 4, 1, 3, 1, 4, 5, 23, 1, 3, 49, 5, 17, 4, 1, 3, 11, 4, 19, 29, 1, 3, 1, 31, 7, 4, 13, 3, 1, 4, 23, 5, 1, 3, 1, 37, 5, 4, 11, 3, 1, 4, 9, 41, 1, 3, 17, 43, 29, 4, 1, 3, 13, 4, 31, 47, 19, 3, 1, 7, 9, 4, 1, 3, 1, 4, 5 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..10000

FORMULA

If A020639(n)^2 divides n [when n is in A283050] and either A119288(n) = 1 or A020639(n)^2 < A119288(n), then a(n) = A020639(n)^2, otherwise a(n) = A119288(n).

PROG

(PARI) A292269(n) = { my(ds=divisors(n)); if(numdiv(n)<3, 1, ds[3]); }

(Scheme) (define (A292269 n) (let ((x (A000290 (A020639 n))) (y (A119288 n))) (if (and (zero? (modulo n x)) (or (= 1 y) (< x y))) x y)))

CROSSREFS

Cf. A000005, A020639, A119288, A171783, A283050, A284255, A284260.

Cf. A008578 (positions of ones).

Sequence in context: A094804 A232633 A089612 * A010127 A263022 A326690

Adjacent sequences:  A292266 A292267 A292268 * A292270 A292271 A292272

KEYWORD

nonn

AUTHOR

Antti Karttunen, Oct 04 2017

STATUS

approved

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Last modified April 9 17:35 EDT 2020. Contains 333361 sequences. (Running on oeis4.)