OFFSET
-323,1
COMMENTS
Smallest positive representable value in IEEE-754 double-precision floating-point format when subnormal numbers (or denormalized numbers) are supported. See the Wikipedia link below for the double-precision representation of this number (sixty-three 0's and one 1).
The last term is a(427) = 5.
Some other facts about double-precision numbers: (i) there are 2^64 - 2^53 - 1 = 18437736874454810623 representable numbers, because all 1's in the 11-bit exponent results in positive or negative infinity (depending on the sign bit), and 0 has two representations (all 0's or one 1 followed by sixty-three 0's); (ii) the largest representable number is 2^1024 - 2^971 = 1.7976931348623157...*10^308 (sign bit = 0, exponent = 11111111110, fraction = fifty-two 1's); (iii) the smallest non-representable positive integer is 2^53 + 1 = 9007199254740993. [Extended by Jianing Song, Apr 27 2019]
LINKS
Jianing Song, Table of n, a(n) for n = -323..427 (full sequence)
Wikipedia, Double-precision floating-point format
EXAMPLE
2^(-1074) = 4.9406564584124654417...*10^(-324).
MAPLE
evalf[120](2^(-1074)); # Muniru A Asiru, Nov 24 2018
MATHEMATICA
First[RealDigits[N[2^(-1074), 100], 10]] (* Stefano Spezia, Nov 01 2018 *)
PROG
(PARI) a(n) = if(n>=-323&&n<=427, digits(5^1074)[n+324], 0)
CROSSREFS
KEYWORD
AUTHOR
Jianing Song, Oct 31 2018
STATUS
approved