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A081509
Primes of the form 1 + 2^k + 4^k + 6^k.
1
13, 366993409, 789800591806169089, 8145612997113849913833354347764846494983651329
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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
Table of n, a(n) for n=1..4.
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
Adjacent sequences:
A081506
A081507
A081508
*
A081510
A081511
A081512
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.)