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A225206
Number of Pythagorean quadruples (a, b, c, d) with d < 10^n.
3
6, 571, 56268, 5614390, 561232920, 56120665334, 5612026652893, 561202243017532, 56120219419339591
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OFFSET
1,1
COMMENTS
a(n) ~ Pi*
A225207
(n)/(1+G), where G is Catalan's constant (
A006752
).
LINKS
Table of n, a(n) for n=1..9.
Wikipedia,
Pythagorean quadruple
FORMULA
a(n) = Sum_{k=1..10^n-1}
A181786
(k). -
Max Alekseyev
, Feb 28 2023
EXAMPLE
a(1) = 6 because there are six solutions (a, b, c, d) as follows: (1, 2, 2, 3), (2, 4, 4, 6), (2, 3, 6, 7), (1, 4, 8, 9), (3, 6, 6, 9), (4, 4, 7, 9) with d < 10.
CROSSREFS
Cf.
A169580
,
A181786
,
A225207
.
Sequence in context:
A029590
A332156
A291953
*
A268207
A268247
A345024
Adjacent sequences:
A225203
A225204
A225205
*
A225207
A225208
A225209
KEYWORD
more
,
nonn
AUTHOR
Arkadiusz Wesolowski
, May 01 2013
EXTENSIONS
a(4) from
Giovanni Resta
, May 01 2013
a(5)-a(9) from
Max Alekseyev
, Feb 28 2023
STATUS
approved
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Last modified April 23 22:36 EDT 2024. Contains 371917 sequences. (Running on oeis4.)