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A090112
a(n)=pi(n)*[pi(n)-pi(n-2)] where pi(n)=A000720(n).
1
0, 1, 4, 2, 3, 3, 4, 4, 0, 0, 5, 5, 6, 6, 0, 0, 7, 7, 8, 8, 0, 0, 9, 9, 0, 0, 0, 0, 10, 10, 11, 11, 0, 0, 0, 0, 12, 12, 0, 0, 13, 13, 14, 14, 0, 0, 15, 15, 0, 0, 0, 0, 16, 16, 0, 0, 0, 0, 17, 17, 18, 18, 0, 0, 0, 0, 19, 19, 0, 0, 20, 20, 21, 21, 0, 0, 0, 0, 22, 22, 0, 0, 23, 23, 0, 0, 0, 0, 24, 24
OFFSET
1,3
CROSSREFS
KEYWORD
nonn
AUTHOR
Labos Elemer, Jan 08 2004
STATUS
approved