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”).

A261813
Decimal expansion of (Pi/4)^N*(N^N/N!)^2 for N = 3.
1
9, 8, 1, 0, 5, 7, 9, 7, 3, 0, 8, 7, 6, 1, 1, 4, 9, 7, 7, 3, 9, 6, 8, 0, 2, 8, 1, 4, 2, 0, 0, 0, 5, 0, 8, 2, 5, 7, 0, 4, 0, 9, 5, 2, 1, 0, 2, 9, 9, 5, 8, 4, 8, 5, 6, 3, 5, 0, 4, 2, 0, 2, 5, 9, 4, 0, 7, 4, 9, 2, 1, 4, 1, 8, 5, 4, 3, 8, 3, 5, 5, 0, 9, 4, 8, 8, 3, 8, 9, 9, 8, 5, 9, 7, 0, 0, 6, 9, 5, 9, 5, 1, 3, 4, 3
OFFSET
1,1
COMMENTS
The general expression is a lower bound (due to H. Minkowski) on the discriminant of a number field of degree N.
The corresponding value for N = 2 matches A091476.
REFERENCES
B. Mazur, Algebraic Numbers, in The Princeton Companion to Mathematics, Editor T. Gowers, Princeton University Press, 2008, Section IV.1, page 330.
LINKS
FORMULA
Equals 81*Pi^3/256.
EXAMPLE
9.8105797308761149773968028142000508257040952102995848563504202594...
MATHEMATICA
n = 3; First@ RealDigits[N[(Pi/4)^n (n^n/n!)^2, 120]] (* Michael De Vlieger, Nov 19 2015 *)
PROG
(PARI) N=3; (Pi/4)^N*(N^N/N!)^2
CROSSREFS
Cf. A000796, A091476 (N=2).
Sequence in context: A155683 A343469 A376790 * A373863 A198920 A354593
KEYWORD
nonn,cons
AUTHOR
Stanislav Sykora, Nov 19 2015
STATUS
approved