A026102 a(n) = T(2n-1,n), where T is the array in A026098.

1, 6, 15, 28, 55, 78, 119, 152, 230, 290, 372, 444, 574, 645, 752, 901, 1062, 1159, 1273, 1491, 1606, 1817, 1992, 2314, 2522, 2828, 2987, 3210, 3270, 3616, 4191, 4323, 4658, 5004, 5364, 5738, 6123, 6357, 6847, 7266, 7697, 7964, 8595, 8685, 9259, 9552, 10339, 10927, 11577, 11908

Offset: 1

Author

Clark Kimberling

Keywords

• nonn

Crossrefs

Cf. A001844, A026098.

Cf. A033286. [R. J. Mathar, Oct 22 2008]

Programs

Mathematica

T[1, 1] = 1; T[2, 1] = 3; T[2, 2] = 2; T[n_, 1] := Prime[n];
T[n_, k_] := T[n, k] = Module[{m, mp, jtt}, For[m = 1, True, m++, mp = m Prime[n+1-k]; jtt = Join[Table[T[i, j], {i, 1, n-1}, {j, 1, i}] // Flatten, Table[T[n, j], {j, 1, k-1}]]; If[FreeQ[jtt, mp], Return[mp]]]];
a[n_] := T[2n-1, n]; (* Jean-François Alcover, Sep 05 2019 *)

PARI

lista(nn) = {my(all = []); for (n=1, nn, my(row = getrow(n, all)); if (n % 2, print1(row[(n+1)/2], ", ")); all = Set(concat(all, row)););} \\ uses getrow from A026098; Michel Marcus, Sep 04 2019

Formula

a(n) = A026098(A001844(n)). - Sean A. Irvine, Sep 16 2019

Extensions

Corrected and extended by Michel Marcus, Sep 04 2019