OFFSET
1,3
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..44497
MATHEMATICA
Accumulate@ Array[Boole@ PrimeQ[2^# - 1] &, 107] (* Michael De Vlieger, Feb 09 2020 *)
With[{mpe=MersennePrimeExponent[Range[47]]}, Accumulate[Table[If[ MemberQ[ mpe, n], 1, 0], {n, 120}]]] (* Harvey P. Dale, Aug 22 2021 *)
PROG
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Feb 09 2020
STATUS
approved