

A224502


Prime numbers (together with one) whose representation in balanced ternary are palindromes.


3



1, 7, 13, 43, 61, 73, 103, 367, 421, 457, 547, 601, 613, 757, 859, 1039, 1093, 3823, 4021, 4561, 4723, 4759, 5743, 6211, 6373, 6481, 6949, 7219, 7489, 7933, 8563, 8941, 9103, 9679, 29527, 30013, 31147, 31741, 33037, 35251, 36061, 36097, 36583, 37717, 39607, 41011, 42667, 43963, 44773, 45691, 47581, 49201
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OFFSET

1,2


COMMENTS



LINKS



EXAMPLE

For n=5, a(5)=61 and in balanced ternary notation is 1ī1ī1.


PROG

(PARI)
bt(k, n)={
sum(i=0, (n1)\2,
my(t=k%31);
k\=3;
n;
if(n==i, 3^n, 3^i+3^n)*t
)
};
do(N)={
my(v=List([1]), t);
for(n=1, N,
forstep(k=2, 3^((n+1)\2)1, 3,
t=bt(k, n);
if(isprime(t), listput(v, t))
)
);
vecsort(Vec(v))


CROSSREFS



KEYWORD

nonn,base


AUTHOR



STATUS

approved



