A219957 Numbers expressible as 2*p + 3*q exactly in two ways, where p and q are primes (not necessarily distinct).

19, 25, 31, 35, 37, 49, 53, 59, 65, 85, 89

Offset

1,1

Links

Table of n, a(n) for n=1..11.

Example

89 = 2*37 + 3*5 = 2*19 + 3*17.

Mathematica

mx = 1000; s = Table[0, {mx}]; Do[a = 2 Prime[i] + 3 Prime[k]; s[[a]]++, {k, PrimePi[(mx - 4)/3]}, {i, PrimePi[(mx - 3 Prime[k])/2]}]; Flatten@Position[s, 2]

Crossrefs

Cf. A079026, A219955, A219956.

Sequence in context: A363802 A134255 A061841 * A276437 A129071 A066125

Adjacent sequences: A219954 A219955 A219956 * A219958 A219959 A219960

Keyword

nonn,fini,full

Author

Zak Seidov, Dec 02 2012

Status

approved