OFFSET
1,1
COMMENTS
The terms n = 1..26 are prime. This is the longest sequence of primes in arithmetic progression with smallest end, a(26)=12783396861134173, known as of August 10, 2015.
LINKS
Colin Barker, Table of n, a(n) for n = 1..1000
Jens Kruse Andersen, All known AP24 to AP26.
Wikipedia, Largest known primes in AP.
Index entries for linear recurrences with constant coefficients, signature (2,-1).
FORMULA
a(n) = 3486107472997423 + (n-1)*1666981*A002110(9).
G.f.: -x*(3114215897471953*x-3486107472997423) / (x-1)^2. - Colin Barker, Aug 25 2015
EXAMPLE
a(26) = 3486107472997423 + 25*371891575525470 = 12783396861134173 is prime.
MATHEMATICA
Table[3486107472997423 + (n - 1) 371891575525470, {n, 1, 20}]
LinearRecurrence[{2, -1}, {3486107472997423, 3857999048522893}, 20] (* Harvey P. Dale, May 14 2022 *)
PROG
(Magma) [3486107472997423+(n-1)*371891575525470: n in [1..20]];
(PARI) Vec(-x*(3114215897471953*x-3486107472997423)/(x-1)^2 + O(x^40)) \\ Colin Barker, Aug 25 2015
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Marco Ripà, Aug 10 2015
STATUS
approved