A292269 If n is 1 or a prime, then a(n) = 1, otherwise a(n) = the third smallest divisor of n.
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
Offset: 1
Keywords
Links
- Antti Karttunen, Table of n, a(n) for n = 1..10000
Crossrefs
Programs
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Mathematica
a[n_?PrimeQ] = 1; a[1] = 1; a[n_] := Divisors[n][[3]]; Array[a, 100] (* Amiram Eldar, Jan 30 2025 *)
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PARI
A292269(n) = { my(ds=divisors(n)); if(numdiv(n)<3,1,ds[3]); }
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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)))
Comments