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A079490 Exp(n) is closer to an integer than any previous exp(k) for 1 <= k < n. +0
12
1, 3, 8, 19, 45, 75, 135, 178, 209, 732, 1351, 1907, 5469, 28414, 37373 (list; graph; listen)
OFFSET

1,2

REFERENCES

J.-M. De Koninck, Ces nombres qui nous fascinent, Entry 178, p. 56, Ellipses, Paris 2008.

EXAMPLE

a(2) = 3: exp(3) = 20.08... is closer to an integer than exp(1) = 2.718...

At 37373 the difference from an integer is 0.0000010493779591646530966...

MATHEMATICA

a = 1; Do[ d = Abs[ Round[E^n] - N[E^n, Ceiling[ Log[10, E^n] + 10]]]; If[d < a, Print[n]; a = d], {n, 1, 50000}]

PROGRAM

(PARI) {default(realprecision, 1000); d(x)=abs(x-round(x))}; a(n)=local(m); if(n<2, n>0, n=a(n-1); m=d(exp(n)); until(d(exp(n))<m, n++); n)

CROSSREFS

Cf. A000149, A001671, A004790, A080053.

Sequence in context: A121551 A077850 A097550 this_sequence A026789 A096576 A126874

Adjacent sequences: A079487 A079488 A079489 this_sequence A079491 A079492 A079493

KEYWORD

nonn

AUTHOR

Donald S. McDonald (don.mcdonald(AT)paradise.net.nz), Jan 20 2003

EXTENSIONS

Corrected and extended to 1351 by several correspondents, Jan 20 2003

Four further terms from Robert G. Wilson v (rgwv(AT)rgwv.com), Jan 20 2003

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Last modified November 24 14:25 EST 2009. Contains 167438 sequences.


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