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A129738
List of primitive prime divisors of the Jacobsthal numbers A001045 in their order of occurrence.
4
3, 5, 11, 7, 43, 17, 19, 31, 683, 13, 2731, 127, 331, 257, 43691, 73, 174763, 41, 5419, 23, 89, 2796203, 241, 251, 4051, 8191, 87211, 29, 113, 59, 3033169, 151, 715827883, 65537, 67, 20857, 131071, 281, 86171, 37, 109, 1777, 25781083, 524287, 22366891, 61681, 83
OFFSET
1,1
COMMENTS
Read A001045 term-by-term, factorize each term, write down any primes not seen before.
LINKS
Graham Everest, Shaun Stevens, Duncan Tamsett and Tom Ward, Primes generated by recurrence sequences, Amer. Math. Monthly, 114 (No. 5, 2007), 417-431.
K. Zsigmondy, Zur Theorie der Potenzreste, Monatsh. Math., 3 (1892), 265-284.
MAPLE
concat := (a, h)->[op(a), op(sort(convert(h, list)))]:
PPDinOrder := proc(S) local A, H, T, s;
T := {0, 1}; A := [];
for s in S do
H := numtheory[factorset](s) minus T:
if H <> {} then
A := concat(A, H);
T := T union H
fi
od;
A end:
A129738 := PPDinOrder(A001045);
# Peter Luschny, Jan 04 2011
MATHEMATICA
DeleteDuplicates[Flatten[FactorInteger[#][[All, 1]]&/@LinearRecurrence[ {1, 2}, {3, 5}, 50]]](* Harvey P. Dale, Apr 14 2020 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, May 13 2007
STATUS
approved