A102324 Primes of the form Sum[7^i, {i, 0, n}] + 1 - Mod[Sum[7^i, {i, 0, n}], 2].

401, 2801, 19609, 2306881201, 16148168401, 441955140976608911963170563601, 51995580380757061883555053636996009, 103277498764237935298508446601504482183281737967152502422497452803442129350499861144992195052660926412401

Offset

1,1

Comments

a(13) has 1436 decimal digits. - Vincenzo Librandi, Jul 19 2012

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..12

Mathematica

a = Delete[Union[Table[If[PrimeQ[Sum[7^i, {i, 0, n}] + 1 - Mod[Sum[7^i, {i, 0, n}], 2]] == True, Sum[7^i, {i, 0, n}] + 1 - Mod[Sum[7^i, {i, 0, n}], 2], 0], {n, 0, 200}]], 1]

Crossrefs

Sequence in context: A094614 A104926 A031718 * A156785 A031628 A179293

Adjacent sequences: A102321 A102322 A102323 * A102325 A102326 A102327

Keyword

nonn

Author

Roger L. Bagula, Mar 15 2005

Extensions

Corrected a(8). - Vincenzo Librandi, Jul 19 2012

Status

approved