login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A101507
Numbers n such that exp(n) has a smaller relative error abs(exp(n)/m!-1) in approximating the closest factorial m!>1 than exp(k) for any k with 1<k<n.
1
2, 3, 15, 20, 58, 2893, 3172, 13778, 36596, 63894, 208744, 296557, 404667, 11500740, 17800369, 37858613, 38393813, 902477623, 4126573365, 79491128275, 338814192247, 1599109448865
OFFSET
1,1
COMMENTS
Numbers n such that abs(exp(n)/m!-1)<abs(exp(k)/j!-1) with m such that abs(exp(n)-m!)=min for any k with 1<k<n and j such that abs(exp(k)-j!)=min.
EXAMPLE
a(1)=2 because exp(2)=7.389 is a better approximation to the nearest factorial 3!=6 with +23% relative error than is exp(1)=2.718 for its closest factorial 2!=2 with +36% relative error.
a(2)=3: exp(3)/4!-1=-0.1631. The next improvement occurs for a(3)=15 because exp(15)/10!-1=-0.099.
a(22)=1599109448865: The relative error of exp(1599109448865) in approximating A101506(22)!=66836971558! is 1.276*10^(-12).
CROSSREFS
Cf. A101506.
Sequence in context: A331089 A294131 A274003 * A047176 A347668 A325236
KEYWORD
more,nonn
AUTHOR
Hugo Pfoertner, Dec 20 2004
STATUS
approved