A250222 a(n) = phi(2n+1) - phi(2n), where phi is A000010.

1, 2, 4, 2, 6, 8, 2, 8, 12, 4, 12, 12, 6, 16, 22, 4, 8, 24, 6, 24, 30, 4, 24, 26, 12, 28, 22, 12, 30, 44, 6, 16, 46, 12, 46, 48, 4, 24, 54, 22, 42, 40, 14, 48, 48, 16, 26, 64, 18, 60, 70, 0, 54, 72, 32, 64, 52, 16, 38, 78, 20, 40, 90, 20, 82, 68, 6, 72, 94, 44, 50, 64

Offset

1,2

Comments

a(157) = -12 is the first negative number in this sequence.

Links

Table of n, a(n) for n=1..72.

Crossrefs

Cf. A000010, A057000.

Sequence in context: A083791 A303347 A325971 * A026251 A205721 A085190

Adjacent sequences: A250219 A250220 A250221 * A250223 A250224 A250225

Keyword

nonn

Author

Eric Chen, Dec 24 2014

Status

approved