OFFSET
0,2
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..1000
FORMULA
a(n) = A281871(n+9,n).
EXAMPLE
a(1) = 3: {1}, {4}, {9}.
a(2) = 8: {1,3}, {1,8}, {2,7}, {3,6}, {4,5}, {5,11}, {6,10}, {7,9}.
CROSSREFS
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Feb 03 2017
STATUS
approved