A077797 - cp's OEIS frontend

A077797 Numbers k for which there exist k-digit palindromic wing primes (a.k.a. near-repdigit palindromic primes) of the general form r(10^k - 1)/9 + (m-r)10^floor(k/2) where k is the number of digits (an odd number > 1), r is the repeated digit, and m (different from r) is the middle digit.

%I A077797 #15 Aug 11 2024 14:41:34
%S A077797 3,5,7,9,11,13,15,17,19,21,23,25,27,29,35,39,41,45,47,53,59,63,65,67,
%T A077797 73,79,81,87,91,109,117,119,123,139,155,159,171,177,181,185,189,195,
%U A077797 209,225,231,233,237,259,321,325,337,339,355,363,371,375,397,425,453
%N A077797 Numbers k for which there exist k-digit palindromic wing primes (a.k.a. near-repdigit palindromic primes) of the general form r*(10^k - 1)/9 + (m-r)*10^floor(k/2) where k is the number of digits (an odd number > 1), r is the repeated digit, and m (different from r) is the middle digit.
%D A077797 C. Caldwell and H. Dubner, "Journal of Recreational Mathematics", Volume 28, No. 1, 1996-97, pp. 1-9.
%H A077797 P. De Geest, <a href="https://www.worldofnumbers.com/pwpsorted.htm">PWP's Sorted By Length</a>
%Y A077797 Cf. A077775-A077798.
%K A077797 nonn,base
%O A077797 1,1
%A A077797 _Patrick De Geest_, Nov 16 2002
%E A077797 Name edited by _Jon E. Schoenfield_, Nov 04 2018

cp's OEIS Frontend

A077797 Numbers k for which there exist k-digit palindromic wing primes (a.k.a. near-repdigit palindromic primes) of the general form r*(10^k - 1)/9 + (m-r)*10^floor(k/2) where k is the number of digits (an odd number > 1), r is the repeated digit, and m (different from r) is the middle digit.

A077797 Numbers k for which there exist k-digit palindromic wing primes (a.k.a. near-repdigit palindromic primes) of the general form r(10^k - 1)/9 + (m-r)10^floor(k/2) where k is the number of digits (an odd number > 1), r is the repeated digit, and m (different from r) is the middle digit.