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, 11891268400, 24563311308, 50685770166, 104484802056
Offset: 0
Keywords
Links
- Amiram Eldar, Table of n, a(n) for n = 0..78
- Paul Cooijmans, Numbers, Item 18, 1995.
- Paul Cooijmans, Short Test For Genius, Item 29, 2002.
Programs
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Mathematica
Prime[2^Range[0,30]]-1 (* Harvey P. Dale, Sep 30 2016 *)
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PARI
a(n) = prime(2^n) - 1; \\ Amiram Eldar, Jul 11 2025
Formula
a(n) = A033844(n) - 1.
a(n) = A051440(n) - 2. - Amiram Eldar, Jul 11 2025
Extensions
More terms from Amiram Eldar, Jul 11 2025