cp's OEIS Frontend

A246135 Primes that are palindromic right angle numbers in base 9.

%I A246135 #13 Jun 02 2025 10:13:51
%S A246135 173,191,373,719,50767,1270271,30890747159
%N A246135 Primes that are palindromic right angle numbers in base 9.
%e A246135 50767 is in the list since it is prime and is equal to 76567 in base 9.
%o A246135 (Python)
%o A246135 from sympy import isprime
%o A246135 A246135 = []
%o A246135 for n in range(1,9):
%o A246135     for m in range(n-1, -1, -1):
%o A246135         l = ''.join([str(d) for d in range(n, m-1, -1)])
%o A246135         p = int(l+l[-2::-1], 9)
%o A246135         if isprime(p):
%o A246135             A246135.append(p)
%o A246135     for m in range(n+1, 9):
%o A246135         l = ''.join([str(d) for d in range(n, m+1)])
%o A246135         p = int(l+l[-2::-1], 9)
%o A246135         if isprime(p):
%o A246135             A246135.append(p)
%o A246135 A246135 = sorted(A246135)
%Y A246135 Cf. A246136, A244369.
%K A246135 nonn,base,full,fini
%O A246135 1,1
%A A246135 _Chai Wah Wu_, Aug 15 2014