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A145682 The value of the sum shown in the display appears to 2, 8, 32 - sqrt(2), 113, 382, 833, 1822, 3713, 7582, ... for n = 1, ..., 9. 1
2, 8, 32, 113, 382, 833, 1822, 3713, 7582 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
This is an unusual sequence mentioned on the Math Fun Mailing list. It does not quite fit the format of regular OEIS entries, but is too interesting to be forgotten. - N. J. A. Sloane, Mar 29 2009
The definition arises from the Fourier series for the Snowflake curve.
..................................................................
.............................. inf ...............................
.............................. ==== ............ m ...............
............................ k \ ....... %pi (k 2..- 5) ..... n ..
....................... (- 1).. > .. tan(--------------) (- 1) ...
............. inf ............ / ............ n + m ..............
............. ==== ........... ==== ........ 2 ...................
..... 5 m - 1 \ .............. n = 1 .............................
.. 3 2 ....... > ...... --------------------------------------- ..
............. / .................................... m ...........
............. ==== .......... m ... 3 ... 10 %pi (k 2 .- 5) ......
............. k = - inf . (k 2..- 5)..csc(-----------------) .....
................................................ 2 m .............
............................................... 2 ................
.. ------------------------------------------------------------ ..
........................... 3 ... 5 %pi ..........................
........................ %pi..csc(-----) .........................
................................... m ............................
.................................. 2 .............................
LINKS
CROSSREFS
Sequence in context: A052481 A306292 A067897 * A363109 A289451 A230509
KEYWORD
nonn
AUTHOR
Bill Gosper, Apr 12 2005
STATUS
approved

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Last modified May 26 04:31 EDT 2024. Contains 372807 sequences. (Running on oeis4.)