A138905 -id:A138905 - cp's OEIS frontend

A138907 a(n) = A138906(n) - A138905(n).

2, 14, 2, 74, 32, 2, 2, -94, -52, 482, -262, 578, 2, 590, 452, 386, -814, 326, 1598, 1202, 758, 530, -1516, 290, 602, -154, -1618, 2354, 2612, 1442, 2420, -3646, 794, 1430, 1472, -862, -220, 1142, 938, 2642, -2458, 3782, 4130, 3698, 1622, 5798, 3386, -3742, 2, 6002, -8566, -1246, 2864, 3566, 1322, 2690, 3764

Offset: 1

Zak Seidov, Apr 03 2008

sign

Cf. A138905, A138906.

a138906[n_]:=Module[{p=1,cnt=0},Until[cnt==n,If[Mod[Prime[p],6n]==1,cnt++];p++];Prime[p-1]];a138905[n_]:=Module[{p=1,cnt=0},Until[cnt==n,If[Mod[Prime[p],6n]==6n-1,cnt++];p++];Prime[p-1]];Table[a138906[n]-a138905[n],{n,57}] (* James C. McMahon, Jun 23 2025 *)

a(41) corrected by James C. McMahon, Jun 23 2025

A138906 a(n) is n-th prime == 1 (mod 6n).

Original entry on oeis.org

7, 37, 73, 241, 211, 433, 463, 769, 811, 1321, 1321, 2089, 1951, 2689, 2791, 4513, 3469, 5077, 6271, 6121, 6427, 7129, 7177, 10369, 7951, 10453, 10531, 13441, 15139, 12601, 18229, 15937, 17623, 21013, 15331, 24841, 23977, 26449, 24571, 24481

Offset: 1

Zak Seidov, Apr 03 2008

nonn

Cf. A138905, A138907.

a[n_]:=Module[{p=1,cnt=0},Until[cnt==n,If[Mod[Prime[p],6n]==1,cnt++];p++];Prime[p-1]];Array[a,40] (* James C. McMahon, Jun 23 2025 *)

cp's OEIS Frontend

A138907 a(n) = A138906(n) - A138905(n).

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