login
A098102
a(n) = 2^(prime(n) - 1) - 1 where prime(n) is the n-th prime.
5
1, 3, 15, 63, 1023, 4095, 65535, 262143, 4194303, 268435455, 1073741823, 68719476735, 1099511627775, 4398046511103, 70368744177663, 4503599627370495, 288230376151711743, 1152921504606846975
OFFSET
1,2
EXAMPLE
For n = 3; prime(3) = 5, a(3) = 2^(5-1) - 1 = 15.
MATHEMATICA
Table[2^(Prime[n] - 1) - 1, {n, 20}]
PROG
(Magma)[2^(NthPrime(n)-1) - 1: n in [1..18]] // Jaroslav Krizek, Jan 02 2015
(PARI) a(n) = 2^(prime(n)-1) - 1; \\ Michel Marcus, Jan 13 2023
CROSSREFS
Sequence in context: A083858 A151241 A080948 * A144067 A001447 A106732
KEYWORD
nonn
AUTHOR
Parthasarathy Nambi, Sep 22 2004
EXTENSIONS
Edited and extended by Robert G. Wilson v, Sep 23 2004
Definition and example corrected by Jaroslav Krizek, Jan 02 2015
Name edited by Michel Marcus, Jan 13 2023
STATUS
approved