Odd numbers k such that the palindromic wing number (a.k.a. near-repdigit palindrome) 7*(10^k - 1)/9 - 2*10^((k-1)/2) is prime.

A077785

Odd numbers k such that the palindromic wing number (a.k.a. near-repdigit palindrome) 7*(10^k - 1)/9 - 2*10^((k-1)/2) is prime.

Terms

    a(0) =3a(1) =15a(2) =27a(3) =117a(4) =259a(5) =507a(6) =3315a(7) =4489a(8) =4875a(9) =15849a(10) =19807a(11) =23799a(12) =36315a(13) =37915a(14) =47331a(15) =211219

External references