OFFSET
1,2
LINKS
Eric Weisstein's World of Mathematics, Root-Mean-Square
EXAMPLE
a(7) = 11 subsets: {2}, {3}, {5}, {7}, {11}, {13}, {17}, {7, 17}, {5, 7, 17}, {7, 13, 17} and {5, 7, 11, 17}.
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Dec 08 2020
EXTENSIONS
a(10)-a(40) from Alois P. Heinz, Dec 08 2020
STATUS
approved