|
|
A350964
|
|
a(n) is the largest prime factor of 2^p - p^2 where p is the n-th prime.
|
|
2
|
|
|
7, 79, 47, 113, 130783, 523927, 1198297, 240641, 641, 575058377, 1519711993, 65929327, 20105355479017, 9007199254738183, 7633399, 33189241, 21081993227096629777, 951850902549409, 4978773308244222679, 501615233613780359, 9671406556917033397642519, 8251206137, 3818597055399121, 13314319257913, 521211122055087383048446607
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
3,1
|
|
COMMENTS
|
|
|
REFERENCES
|
E.-B. Escott, Note #1642, L'Intermédiaire des Mathématiciens, 8 (1901), page 12.
|
|
LINKS
|
|
|
FORMULA
|
|
|
MAPLE
|
a:= n-> max(numtheory[factorset]((p-> 2^p-p^2)(ithprime(n)))):
|
|
MATHEMATICA
|
a[n_] := FactorInteger[2^(p = Prime[n]) - p^2][[-1, 1]]; Array[a, 25, 3] (* Amiram Eldar, Mar 03 2022 *)
|
|
PROG
|
(PARI) a(n) = my(p=prime(n)); vecmax(factor(2^p - p^2)[, 1]); \\ Michel Marcus, Mar 03 2022
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|