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A093708 Number of odd nonprime differences of 2 (twin odd nonprimes) below 10^n. 0
0, 9, 200, 2748, 32041, 351174, 3729823, 38917403, 401729439, 4117307658, 41988266423, 426654761185, 4323703591195, 43725896820062, 441488068396967, 4451827503629449 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..16.

FORMULA

Count twin odd nonprimes below 10^n

a(n) = 10^n/2 - 2*A006880(n) + A007508(n) + 1 - Max Alekseyev, May 11 2005

EXAMPLE

a(2)=9 because under 100 there are 9 twin odd nonprimes, e.g. 27-25=2.

CROSSREFS

Cf. A093683 A006880 A007508.

Sequence in context: A196910 A064756 A197077 * A052145 A012061 A012168

Adjacent sequences:  A093705 A093706 A093707 * A093709 A093710 A093711

KEYWORD

easy,nonn

AUTHOR

Enoch Haga, Apr 10 2004

EXTENSIONS

More terms from Max Alekseyev, May 11 2005

STATUS

approved

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Last modified May 19 12:49 EDT 2019. Contains 323393 sequences. (Running on oeis4.)