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A309541
Representable positive integers n that are not the inverse of their inverse in binary64 (double precision) IEEE 754 floating-point arithmetic (Version where 1 and n*(1/n) are unequal).
1
49, 98, 103, 107, 161, 187, 196, 197, 206, 214, 237, 239, 249, 253, 322, 347, 374, 389, 392, 394, 412, 417, 425, 428, 443, 474, 478, 479, 491, 498, 499, 501, 503, 506, 509, 561, 569, 644, 685, 691, 694, 725, 729, 735, 737, 748, 753, 765, 778, 779, 784, 788, 789, 797, 809, 817, 823, 824, 829, 833, 834, 837, 841, 849, 850
OFFSET
1,1
LINKS
Efstratios Gallopoulos, Scientific Computation I, five terms provided (in Greek) [broken link]
Mark, comment on blog post "Rundungsfehler im Flash Player?", eight terms (in German)
koDoz, comment in thread "Welche Grenzwerte gelten für Zahlen, Strings usw?", nine terms (in German)
PROG
(Python 2 or Python 3)
for i in range(1, 1000):
if i*(1./i) != 1: print(i)
(Fortran)
doubleprecision one, r
integer i
parameter (one=1.0D0)
do 10 i = 1, 500
R = one / dble(i)
if ( R * dble(i) .ne. one) write (*, 1000) i
1000 format (i0)
10 continue
end
C Hugo Pfoertner, Jan 18 2024
CROSSREFS
See A275419 for the n != 1/(1/n) version.
Sequence in context: A044030 A165339 A131601 * A174386 A044138 A043394
KEYWORD
nonn,fini
AUTHOR
Adam M. Scherlis, Aug 06 2019
STATUS
approved