OFFSET
0,3
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..20000
EXAMPLE
a(1) = 1: {2}.
a(2) = 2: {1,2}, {2,3}.
a(3) = 1: {1,2,4}.
a(4) = 2: {1,2,3,5}, {1,3,4,5}.
a(5) = 2: {1,2,3,5,6}, {1,3,4,5,6}.
a(6) = 1: {1,2,3,4,6,7}.
a(7) = 2: {1,2,3,4,5,6,8}, {1,2,3,4,6,7,8}.
a(8) = 3: {1,2,3,4,5,6,7,9}, {1,2,3,5,6,7,8,9}, {1,3,4,5,6,7,8,9}.
MAPLE
a:= proc(n) option remember; (t-> add(`if`(isprime(
t-i), 1, 0), i=1..n+1))((n+1)*(n+2)/2)
end:
seq(a(n), n=0..100);
CROSSREFS
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Feb 17 2017
STATUS
approved