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