A018249 a(n) = prime(2^n)-1.

1, 2, 6, 18, 52, 130, 310, 718, 1618, 3670, 8160, 17862, 38872, 84016, 180502, 386092, 821640, 1742536, 3681130, 7754076, 16290046, 34136028, 71378568, 148948138, 310248240, 645155196, 1339484196, 2777105128, 5750079046

Offset

0,2

Links

Table of n, a(n) for n=0..28.

Paul Cooijmans, Numbers, Item 18.

Paul Cooijmans, Short Test For Genius, Item 29.

Mathematica

Prime[2^Range[0, 30]]-1 (* Harvey P. Dale, Sep 30 2016 *)

Crossrefs

Equals A033844 - 1. Cf. A000040, A033844, A051438, A051440, A051439.

Sequence in context: A219136 A192237 A034525 * A374186 A245285 A128104

Adjacent sequences: A018246 A018247 A018248 * A018250 A018251 A018252

Keyword

nonn,easy

Author

N. J. A. Sloane.

Status

approved