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A081509 Primes of the form 1 + 2^k + 4^k + 6^k. 1
13, 366993409, 789800591806169089, 8145612997113849913833354347764846494983651329 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
a(5) has 311 digits. - Harvey P. Dale, Mar 18 2019
Using the above, a(5) = 1 + 2^399 + 4^399 + 6^399. - David A. Corneth, Mar 18 2019
LINKS
EXAMPLE
n=1: 1 + 2 + 4 + 6 = 13 is prime.
MATHEMATICA
Do[s=1^w+2^w+4^w+6^w; If[IntegerQ[w/100], Print[{w}]]; If[PrimeQ[s], Print[{w, s}]], {w, 0, 1000}]
Select[Table[1+2^n+4^n+6^n, {n, 60}], PrimeQ] (* Harvey P. Dale, Mar 18 2019 *)
CROSSREFS
Cf. A081510.
Sequence in context: A158750 A145744 A174309 * A177224 A145234 A334634
KEYWORD
nonn
AUTHOR
Labos Elemer, Apr 15 2003
STATUS
approved

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Last modified June 13 23:50 EDT 2024. Contains 373391 sequences. (Running on oeis4.)