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A134193 a(1) = 1; for n>1, a(n) = the smallest positive integer not occurring among the exponents in the prime-factorization of n. 4
1, 2, 2, 1, 2, 2, 2, 1, 1, 2, 2, 3, 2, 2, 2, 1, 2, 3, 2, 3, 2, 2, 2, 2, 1, 2, 1, 3, 2, 2, 2, 1, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 2, 3, 3, 2, 2, 2, 1, 3, 2, 3, 2, 2, 2, 2, 2, 2, 2, 3, 2, 2, 3, 1, 2, 2, 2, 3, 2, 2, 2, 1, 2, 2, 3, 3, 2, 2, 2, 2, 1, 2, 2, 3, 2, 2, 2, 2, 2, 3, 2, 3, 2, 2, 2, 2, 2, 3, 3, 1, 2, 2, 2, 2, 2, 2 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

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

Index entries for sequences computed from exponents in factorization of n

FORMULA

a(n) = A257993(A181819(n)). - Antti Karttunen, Jul 28 2017

EXAMPLE

The prime factorization of 24 is 2^3 * 3^1. The exponents are 3 and 1. Therefore a(24) = 2 is the smallest positive integer not occurring among (3,1).

MATHEMATICA

Table[Complement[Range[n], Table[FactorInteger[n][[i, 2]], {i, 1, Length[FactorInteger[n]]}]][[1]], {n, 2, 120}] (* Stefan Steinerberger, Jan 21 2008 *)

PROG

(Scheme) (define (A134193 n) (A257993 (A181819 n))) ;; Antti Karttunen, Jul 28 2017

(PARI) a(n) = if (n==1, 1, my(f=factor(n)); ve = vecsort(f[, 2], , 8); k = 1; while(vecsearch(ve, k), k++); k; ); \\ Michel Marcus, Jul 28 2017

CROSSREFS

Cf. A136567, A181819, A257993.

Sequence in context: A072463 A128853 A136165 * A230259 A085030 A078377

Adjacent sequences:  A134190 A134191 A134192 * A134194 A134195 A134196

KEYWORD

nonn

AUTHOR

Leroy Quet, Jan 13 2008

EXTENSIONS

More terms from Stefan Steinerberger, Jan 21 2008

STATUS

approved

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