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A282671 Twice composite numbers. 0
8, 12, 16, 18, 20, 24, 28, 30, 32, 36, 40, 42, 44, 48, 50, 52, 54, 56, 60, 64, 66, 68, 70, 72, 76, 78, 80, 84, 88, 90, 92, 96, 98, 100, 102, 104, 108, 110, 112, 114, 116, 120, 124, 126, 128, 130, 132, 136, 138, 140, 144, 148, 150, 152, 154, 156, 160, 162, 164, 168, 170, 172, 174 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Even numbers greater than 2 that do not appear in A001747.

LINKS

Table of n, a(n) for n=1..63.

FORMULA

a(n) = 2*A002808(n). - R. J. Mathar, Feb 23 2017

a(n) = A139270(n+1). - R. J. Mathar, Feb 25 2017

PROG

(PARI) is(n)=n%2==0 && n>6 && !isprime(n/2) \\ Charles R Greathouse IV, Feb 21 2017

CROSSREFS

Cf. A001747, A139270, A176100.

Sequence in context: A111087 A166083 A091375 * A192991 A083348 A174261

Adjacent sequences:  A282668 A282669 A282670 * A282672 A282673 A282674

KEYWORD

nonn,easy

AUTHOR

Alessandro Polcini, Feb 20 2017

STATUS

approved

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Last modified March 21 10:27 EDT 2019. Contains 321368 sequences. (Running on oeis4.)