OFFSET
0,1
COMMENTS
Perhaps m = 105 is the largest number such that m - 2^n is prime for all 1 < n < log_2 m. Indeed 105 - 2^n is also prime for quite a few n > 6.7142455... For n = 9 we have 105 - 512 = -407 = (-1) * 11 * 37, the first instance of a composite term after a(0).
LINKS
Erich Friedman, What's Special About This Number? Entry for 105.
Index entries for linear recurrences with constant coefficients, signature (3,-2).
FORMULA
G.f.: (104 - 209*x)/((1 - x)*(1 - 2*x)). - Bruno Berselli, May 22 2017
MATHEMATICA
105 - 2^Range[0, 31]
PROG
(PARI) vector(40, n, n--; 105-2^n) \\ Bruno Berselli, May 22 2017
(Python) [105-2**n for n in range(40)] # Bruno Berselli, May 22 2017
(Sage) [105-2^n for n in range(40)] # Bruno Berselli, May 22 2017
(Magma) [105-2^n: n in [0..40]]; // Bruno Berselli, May 22 2017
CROSSREFS
KEYWORD
sign,easy
AUTHOR
Alonso del Arte, May 21 2017
STATUS
approved