A337006 Number of distinct pairs of externally tangent circles with radius sqrt(2) and center (p,q) where p and q are prime, p + q = A187797(n) and p <= q.

1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 2, 1, 2, 2, 1, 1, 1, 3, 2, 1, 2, 1, 1, 2, 2, 1, 2, 2, 3, 1, 3, 1, 1, 2, 1, 3, 1, 2, 6, 1, 3, 1, 1, 2, 4, 1, 3, 4, 4, 1, 3, 1, 1, 3, 1, 5, 2, 6, 1, 3, 1, 2, 2, 5, 2, 5, 2, 1, 3, 1, 2, 3, 5, 2, 4, 3, 1, 6, 1, 2, 3, 1, 3, 1, 5, 1, 5, 1

Offset

1,11

Links

Table of n, a(n) for n=1..95.

Mathematica

Table[If[Sum[(PrimePi[i] - PrimePi[i - 1]) (PrimePi[2n - i] - PrimePi[2n - i - 1]) (PrimePi[i - 2] - PrimePi[i - 3]) (PrimePi[2n - i + 2] -PrimePi[2n - i + 1]), {i, 3, n}] > 0, Sum[(PrimePi[i] - PrimePi[i - 1]) (PrimePi[2n - i] - PrimePi[2n - i - 1]) (PrimePi[i - 2] - PrimePi[i - 3]) (PrimePi[2n - i + 2] - PrimePi[2n - i + 1]), {i, 3, n}], {}], {n, 300}] // Flatten

Crossrefs

Cf. A187797, A302231.

Sequence in context: A254444 A102005 A051700 * A025892 A025883 A111335

Adjacent sequences: A337003 A337004 A337005 * A337007 A337008 A337009

Keyword

nonn

Author

Wesley Ivan Hurt, Aug 11 2020

Status

approved