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A079311 Integer part of length of diagonal of integral rectangle with area n and smallest semiperimeter. 0
1, 2, 3, 2, 5, 3, 7, 4, 4, 5, 11, 5, 13, 7, 5, 5, 17, 6, 19, 6, 7, 11, 23, 7, 7, 13, 9, 8, 29, 7, 31, 8, 11, 17, 8, 8, 37, 19, 13, 9, 41, 9, 43, 11, 10, 23, 47, 10, 9, 11, 17, 13, 53, 10, 12, 10, 19, 29, 59, 11, 61, 31, 11, 11, 13, 12, 67, 17, 23, 12, 71, 12, 73, 37, 15, 19, 13, 14, 79 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

n <= a(n); for n > 1, a(n)=n iff n is prime.

LINKS

Table of n, a(n) for n=1..79.

FORMULA

a(n) = floor(sqrt(A033676(n)^2 + A033677(n)^2)).

MATHEMATICA

Table[Floor@ Sqrt@ Total@ Map[#^2 &, If[IntegerQ@ #, {#, #}, {Last@ #1, First@ #2} & @@ TakeDrop[#, LengthWhile[#, # <= Sqrt@ n &]] &@ Divisors@ n] &@ Sqrt@ n], {n, 79}] (* Michael De Vlieger, Dec 22 2017 *)

CROSSREFS

Cf. A033676, A033677, A063655.

Sequence in context: A116548 A117818 A073890 * A060474 A065988 A075105

Adjacent sequences:  A079308 A079309 A079310 * A079312 A079313 A079314

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Feb 11 2003

STATUS

approved

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Last modified April 18 14:46 EDT 2019. Contains 322209 sequences. (Running on oeis4.)