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A179278 Largest nonprime integer not less than n. 3
1, 1, 1, 4, 4, 6, 6, 8, 9, 10, 10, 12, 12, 14, 15, 16, 16, 18, 18, 20, 21, 22, 22, 24, 25, 26, 27, 28, 28, 30, 30, 32, 33, 34, 35, 36, 36, 38, 39, 40, 40, 42, 42, 44, 45, 46, 46, 48, 49, 50, 51, 52, 52, 54, 55, 56, 57, 58, 58, 60, 60, 62, 63, 64, 65, 66, 66, 68, 69, 70, 70, 72 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

LINKS

Table of n, a(n) for n=1..72.

FORMULA

For n > 3: a(n) = A113523(n) = A014684(n);

For n > 0: a(n) = A113638(n). - Georg Fischer, Oct 12 2018

A005171(a(n)) = 1; A010051(a(n)) = 0.

MATHEMATICA

Array[# - Boole[PrimeQ@ #] - Boole[# == 3] &, 72] (* Michael De Vlieger, Oct 13 2018 *)

PROG

(PARI) a(n) = if (isprime(n), if (n==3, 1, n-1), n); \\ Michel Marcus, Oct 13 2018

CROSSREFS

Cf. A007917, A014684, A018252, A113523, A113638.

Sequence in context: A276679 A163638 A113523 * A132882 A171384 A226833

Adjacent sequences:  A179275 A179276 A179277 * A179279 A179280 A179281

KEYWORD

nonn,easy,changed

AUTHOR

Reinhard Zumkeller, Jul 08 2010

STATUS

approved

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Last modified October 21 19:27 EDT 2018. Contains 316428 sequences. (Running on oeis4.)