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A102822
a(n+1) is the integer part of sqrt(2*a(n)^2).
1
3, 4, 5, 7, 9, 12, 16, 22, 31, 43, 60, 84, 118, 166, 234, 330, 466, 659, 931, 1316, 1861, 2631, 3720, 5260, 7438, 10518, 14874, 21035, 29747, 42068, 59493, 84135, 118984, 168268, 237966, 336534, 475930, 673066, 951859, 1346131, 1903716, 2692260
OFFSET
3,1
COMMENTS
A square of side a(n) has a(n+1) as integer part of its diagonal. - Robert G. Wilson v, Mar 03 2005
Starting the sequence with 0, 1 or 2 would be rather dull.
LINKS
FORMULA
a(n) ~ c * 2^(n/2), where c = 0.6418844655639201638151389885559421955356352362161057500685561808252532289075... - Vaclav Kotesovec, May 23 2021
EXAMPLE
A 3 X 3 square has a diagonal of 4.242640687119285...; the integer part is "4";
a 4 X 4 square has a diagonal of 5.656854249492381...; the integer part is "5";
a 5 X 5 square has a diagonal of 7.071067811865475...; the integer part is "7";
a 7 X 7 square has a diagonal of 9.899494936611665...; the integer part is "9"; etc.
MATHEMATICA
NestList[ Function[x, IntegerPart[ Sqrt[ 2x^2]]], 3, 30] (* Robert G. Wilson v, Mar 03 2005 *)
NestList[IntegerPart[Sqrt[2#^2]]&, 3, 50] (* Harvey P. Dale, Mar 20 2018 *)
CROSSREFS
Sequence in context: A035249 A104805 A260996 * A346986 A167159 A226918
KEYWORD
base,easy,nonn
AUTHOR
Eric Angelini, Feb 27 2005
EXTENSIONS
More terms from Robert G. Wilson v, Mar 03 2005
STATUS
approved