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A051478
a(n) is the number of values k satisfying phi(k) = 4*n+2, n>0.
1
4, 2, 0, 4, 2, 0, 2, 0, 0, 4, 2, 0, 2, 2, 0, 2, 2, 0, 2, 2, 0, 0, 0, 0, 2, 2, 2, 0, 0, 0, 2, 2, 0, 2, 0, 0, 2, 0, 0, 4, 2, 0, 0, 2, 0, 0, 2, 0, 2, 0, 0, 2, 0, 0, 2, 2, 0, 0, 2, 0, 0, 2, 0, 0, 2, 0, 2, 0, 0, 2, 0, 0, 2, 0, 0, 2, 2, 0, 0, 0, 0, 2, 0, 0, 2, 2, 0, 0, 2, 0, 2, 0, 0, 2, 2, 0, 0, 0, 0, 0, 0, 0, 0
OFFSET
1,1
COMMENTS
Sequence consists of only 0's, 2's and 4's.
EXAMPLE
phi(k)=4*1+2 has 4 solutions (k=7, 9, 14, 18), so a(1)=4.
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved