OFFSET
1,1
COMMENTS
LINKS
Daniel Lignon and Charles R Greathouse IV, Table of n, a(n) for n = 1..10000 (first 316 terms from Lignon)
FORMULA
Trivially a(n) << n^2 log^2 n. - Charles R Greathouse IV, Nov 20 2014
EXAMPLE
119 is a term because the nontrivial divisors of 119 are [7,17] and sqrt((7^2+17^2)/2)= 13 : it's an integer.
MATHEMATICA
Select[Range[2, 100000], (Not[PrimeQ[#]] && IntegerQ[ RootMeanSquare[ Rest[ Most[ Divisors[#]]]]])&]
PROG
(PARI) integralRMS(v)=my(t=norml2(v)/#v); denominator(t)==1 && issquare(t)
is(n)=my(d=divisors(n)); #d>2 && integralRMS(d[2..#d-1]) \\ Charles R Greathouse IV, Nov 20 2014
CROSSREFS
KEYWORD
nonn
AUTHOR
Daniel Lignon, Nov 20 2014
STATUS
approved