A219959 Smallest integer expressible as 2p + 3q (p, q primes not necessarily distinct) in exactly n ways.

10, 19, 47, 43, 91, 127, 115, 187, 215, 271, 235, 335, 403, 385, 475, 455, 727, 655, 695, 805, 595, 895, 835, 875, 1085, 1235, 1195, 1309, 1015, 1295, 1405, 1675, 1435, 1375, 2005, 1615, 1715, 1975, 2015, 1925, 2335, 1855, 2255, 2035, 2585, 2575, 2765, 2555

Offset

1,1

Links

Zak Seidov, Table of n, a(n) for n = 1..2000

Example

a(1) = 10 because it can be expressed as 2p + 3q in only one way, 2 * 2 + 3 * 2, and is the smallest integer for which this is the case.
a(2) = 19 because it can be expressed as 2p + 3q in only two ways, 2 * 2 + 3 * 5 = 2 * 5 + 3 * 3, and is the smallest integer for which this is the case.

Mathematica

mx = 10000; 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]}]; Table[Position[s, n][[1, 1]], {n, 50}]

Crossrefs

Cf. A079026, A219955, A219956, A219957, A219958.

Sequence in context: A359315 A082659 A088409 * A307344 A330570 A369305

Adjacent sequences: A219956 A219957 A219958 * A219960 A219961 A219962

Keyword

nonn

Author

Zak Seidov, Dec 02 2012

Status

approved