A077717 Primes which can be expressed as a sum of distinct powers of 3.
3, 13, 31, 37, 109, 271, 283, 337, 733, 739, 757, 769, 811, 823, 1009, 1063, 1093, 2269, 2281, 2467, 2521, 2539, 2551, 2917, 2953, 3001, 3037, 3163, 3169, 3187, 3253, 3271, 6571, 6673, 6679, 6841, 7321, 7411, 7537, 7561, 7573, 8761, 8779, 8839, 9001
Offset: 1
Examples
31 = 3^3 + 3 + 1 belongs to this sequence.
Links
- Harvey P. Dale, Table of n, a(n) for n = 1..10000
Programs
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Mathematica
Select[FromDigits[#,3]&/@Tuples[{0,1},10],PrimeQ] (* Harvey P. Dale, Mar 30 2015 *) -
PARI
print1(3); forstep(n=3,1e3,2, if(isprime(t=fromdigits(binary(n),3)), print1(", "t))) \\ Charles R Greathouse IV, Mar 28 2022 -
PARI
is_A077717(n)=vecmax(digits(n,3))<2 && isprime(n) select(is_A077717, [1..9111]) \\ M. F. Hasler, Feb 15 2023
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Python
def is_A077717(n): return A039966(n) and A010051(n) # M. F. Hasler, Feb 15 2023
Extensions
More terms from John W. Layman, Nov 22 2002
Comments