OFFSET
1,2
REFERENCES
The Finnish National Upper secondary Matriculation Examination Long Maths Problem #12 (Mar 18th, 2020) included finding all gridpoints in a [1..100]x[1..100] grid with an integer geometric mean sparked some national interest in gcd integer sequences and their generating algorithms.
LINKS
Edward Krogius, Table of n, a(n) for n = 1..1000
Edward Krogius, Illustration of 310 solutions in 100x100 grid
YLE (Finnish Broadcasting Corporation), 2020 kevät: matematiikka pitkä oppimäärä (In Finnish)
YLE (Finnish Broadcasting Corporation), Abitreenit, Matematiikka, pitkä oppimäärä (In Finnish; katso Tehtävä 12. Geometrisen keskiarvon todennäköisyyksiä, kohta 2)
FORMULA
a(n) = 2*A339026(n) + n^2.
a(n) = A132188(n^2). - Antti Karttunen, Nov 23 2020
PROG
(PARI) A338894(n) = sum(i=1, n*n, sum(j=1, n*n, issquare(i*j))); \\ (Naive implementation) - Antti Karttunen, Nov 23 2020
CROSSREFS
KEYWORD
nonn
AUTHOR
Edward Krogius, Nov 14 2020
STATUS
approved