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A275381 Number of prime factors (with multiplicity) of generalized Fermat number 10^(2^n) + 1. 2
1, 1, 2, 2, 5, 4, 3, 4, 5 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,3
LINKS
FORMULA
a(n) = A001222(A080176(n)). - Felix Fröhlich, Jul 25 2016
EXAMPLE
b(n) = 10^(2^n) + 1.
Complete Factorizations
b(0) = 11
b(1) = 101
b(2) = 73*137
b(3) = 17*5882353
b(4) = 353*449*641*1409*69857
b(5) = 19841*976193*6187457*834427406578561
b(6) = 1265011073*
15343168188889137818369*515217525265213267447869906815873
b(7) = 257*15361*453377*P116
b(8) = 10753*8253953*9524994049*73171503617*P225
MATHEMATICA
Table[PrimeOmega[10^(2^n) + 1], {n, 0, 6}] (* Michael De Vlieger, Jul 26 2016 *)
PROG
(PARI) a(n) = bigomega(factor(10^(2^n)+1))
CROSSREFS
Sequence in context: A217876 A209771 A209751 * A283235 A209763 A209761
KEYWORD
nonn,hard,more
AUTHOR
STATUS
approved

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Last modified March 18 22:56 EDT 2024. Contains 370952 sequences. (Running on oeis4.)