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A074464
Average digit (rounded down) in the decimal expansion of a prime number p, where 2^p-1 is a Mersenne prime.
1
2, 3, 5, 7, 2, 4, 5, 2, 3, 8, 2, 3, 2, 4, 4, 1, 3, 3, 3, 3, 8, 5, 1, 5, 2, 3, 5, 4, 1, 3, 3, 6, 5, 5, 5, 4, 3, 5, 4, 3, 3, 5, 3, 4, 5, 3, 3, 5
OFFSET
1,1
FORMULA
a(n) = A004426(A000043(n)). - Michel Marcus, Aug 04 2018
EXAMPLE
Prime numbers for Mersenne are 2, 3, 5, 7, 13, 17, 19, 31, 61, ..., so the averages of digits rounded down are 2, 3, 5, 7, (1+3)/2 = 2, (1+7)/2 = 4, (1+9)/2 = 5, (3+1)/2 = 2, floor((6+1)/2) = 3, ...
MATHEMATICA
Floor[Mean[IntegerDigits[#]]]&/@MersennePrimeExponent[Range[47]] (* Harvey P. Dale, Apr 19 2019 *)
CROSSREFS
KEYWORD
nonn,base,more
AUTHOR
Y. Kelly Itakura (yitkr(AT)mta.ca), Aug 23 2002
EXTENSIONS
a(21)-a(47) from Ivan Panchenko, Aug 03 2018
a(48) from Amiram Eldar, Oct 16 2024
STATUS
approved