

A085745


2^n + n is a semiprime.


4



2, 11, 23, 34, 59, 69, 87, 95, 119, 123, 129, 171, 197, 239, 341, 425, 455, 471, 515, 519, 635, 765, 959, 1115, 1181, 1210
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OFFSET

0,1


LINKS

Table of n, a(n) for n=0..25.


FORMULA

a(n)=2k <=> A089535(n) is even <=> A089536(n)=2 <=> A089537(n)=4^k/2+k, and for any prime of this form, there is a term a(n)=2k in this sequence.  M. F. Hasler, Oct 08 2009


MATHEMATICA

Select[Range[1300], PrimeOmega[2^#+#]==2&] (* Harvey P. Dale, Dec 18 2014 *)


CROSSREFS

Cf. A089535, A089536, A089537.
Sequences A165767, A165768, A165769 are the analog for 2^nn.  M. F. Hasler, Oct 08 2009
Sequence in context: A158189 A218255 A256481 * A106856 A045387 A103255
Adjacent sequences: A085742 A085743 A085744 * A085746 A085747 A085748


KEYWORD

more,nonn


AUTHOR

Jason Earls, Jul 21 2003


EXTENSIONS

More terms from Ray Chandler, Nov 08 2003
341 from Donovan Johnson, Mar 06 2008
More terms from Sean A. Irvine, Oct 27 2009


STATUS

approved



