

A060444


Table T(n,k) in which nth row lists prime factors of 2^n + 1 (n >= 0), without repetition.


4



2, 3, 5, 3, 17, 3, 11, 5, 13, 3, 43, 257, 3, 19, 5, 41, 3, 683, 17, 241, 3, 2731, 5, 29, 113, 3, 11, 331, 65537, 3, 43691, 5, 13, 37, 109, 3, 174763, 17, 61681, 3, 43, 5419, 5, 397, 2113, 3, 2796203, 97, 257, 673, 3, 11, 251, 4051
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OFFSET

0,1


COMMENTS

Rows have irregular lengths.
The length of row n is A046799(n).


REFERENCES

J. Brillhart et al., Factorizations of b^n + 1. Contemporary Mathematics, Vol. 22, Amer. Math. Soc., Providence, RI, 2nd edition, 1985; and later supplements.


LINKS

T. D. Noe, Rows n = 0..500 of triangle, flattened (derived from Brillhart et al.)
J. Brillhart et al., Factorizations of b^n + 1, Contemporary Mathematics, Vol. 22, Amer. Math. Soc., Providence, RI, 3rd edition, 2002.
S. S. Wagstaff, Jr., The Cunningham Project.


EXAMPLE

2; 3; 5; 3,17; 3,11; 5,13; 3,43; 257; ...


MATHEMATICA

Flatten[Table[Transpose[FactorInteger[2^n+1]][[1]], {n, 0, 25}]] (* Harvey P. Dale, Aug 10 2011 *)


PROG

(PARI) apply( A060444_row(n)=factor(2^n+1)[, 1]~, [0..10]) \\ M. F. Hasler, Nov 19 2018


CROSSREFS

Cf. A001269 (factors with repetition), A046799 (number of prime divisors).
Sequence in context: A244609 A209195 A113222 * A002587 A152814 A280319
Adjacent sequences: A060441 A060442 A060443 * A060445 A060446 A060447


KEYWORD

nonn,tabf


AUTHOR

N. J. A. Sloane


STATUS

approved



