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A066560 Smallest composite number divisible by n. 2
4, 4, 6, 4, 10, 6, 14, 8, 9, 10, 22, 12, 26, 14, 15, 16, 34, 18, 38, 20, 21, 22, 46, 24, 25, 26, 27, 28, 58, 30, 62, 32, 33, 34, 35, 36, 74, 38, 39, 40, 82, 42, 86, 44, 45, 46, 94, 48, 49, 50, 51, 52, 106, 54, 55, 56, 57, 58, 118, 60, 122, 62, 63, 64, 65, 66, 134, 68, 69, 70 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Harry J. Smith, Table of n, a(n) for n = 1..1000

FORMULA

For n>=2: a(n) = 2*n if n prime; otherwise a(n) = n.

PROG

(PARI) { for (n=1, 1000, if (isprime(n), a=2*n, a=n); if (n==1, a=4); write("b066560.txt", n, " ", a) ) } \\ Harry J. Smith, Mar 02 2010

CROSSREFS

Sequence in context: A131089 A256486 A204068 * A205031 A276683 A247343

Adjacent sequences:  A066557 A066558 A066559 * A066561 A066562 A066563

KEYWORD

nonn

AUTHOR

Amarnath Murthy, Dec 17 2001

EXTENSIONS

More terms and formula from Francisco Salinas (franciscodesalinas(AT)hotmail.com), Dec 24 2001

STATUS

approved

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Last modified January 19 18:13 EST 2020. Contains 331051 sequences. (Running on oeis4.)