A220162 Smallest prime expressible as 2p + 3q (p, q primes) exactly in n ways.

13, 19, 47, 43, 97, 127, 151, 227, 223, 271, 467, 487, 571, 601, 523, 691, 727, 967, 853, 1151, 1051, 1213, 1451, 1303, 1607, 1579, 1523, 1867, 1531, 1951, 1999, 1987, 2239, 2647, 2243, 2663, 2767, 2683, 3037, 2917, 3187, 3259, 3407, 3673, 3823, 3797, 4231

Offset

1,1

Links

Zak Seidov, Table of n, a(n) for n = 1..200

Example

13 = 2*2 + 3*3,
19 = 2*2 + 3*5 = 2*5 + 3*3,
47 = 2*7 + 3*11 = 2*13 + 3*7 = 2*19 + 3*3.

Mathematica

mx = 50000; s = Table[0, {mx}]; Do[p = Prime[k]; Do[a = 2 Prime[i] + 3 p ; s[[a]]++, {i, PrimePi[(mx - 3 p)/2]}], {k, PrimePi[(mx - 4)/3]}]; ta = Table[s[[Prime[k]]], {k, PrimePi[mx ]}]; Table[{k, Prime[Position[ta, k][[1, 1]]]}, {k, 200}] (* for b-file *)

Crossrefs

Cf. A079026, A219955, A219956, A219957, A219958, A219959.

Sequence in context: A174152 A103176 A156940 * A248483 A274424 A180528

Adjacent sequences: A220159 A220160 A220161 * A220163 A220164 A220165

Keyword

nonn

Author

Zak Seidov, Dec 06 2012

Status

approved