cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A077795 Numbers k such that (10^k - 1)/9 + 8*10^floor(k/2) is a palindromic wing prime (a.k.a. near-repdigit palindromic prime).

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%I A077795 #27 Jan 30 2025 17:36:13
%S A077795 3,9,53,375,453,1749,26619,68033,85179
%N A077795 Numbers k such that (10^k - 1)/9 + 8*10^floor(k/2) is a palindromic wing prime (a.k.a. near-repdigit palindromic prime).
%C A077795 Prime versus probable prime status and proofs are given in the author's table.
%C A077795 a(10) > 400000. - _Robert Price_, Jan 30 2025
%D A077795 C. Caldwell and H. Dubner, "Journal of Recreational Mathematics", Volume 28, No. 1, 1996-97, pp. 1-9.
%H A077795 Patrick De Geest, World!Of Numbers, <a href="http://www.worldofnumbers.com/wing.htm#pwp191">Palindromic Wing Primes (PWP's)</a>
%H A077795 Makoto Kamada, <a href="https://stdkmd.net/nrr/1/11911.htm#prime">Prime numbers of the form 11...11911...11</a>
%H A077795 <a href="/index/Pri#Pri_rep">Index entries for primes involving repunits</a>.
%F A077795 a(n) = 2*A107649(n) + 1.
%e A077795 9 is a term because (10^9 - 1)/9 + 8*10^4 = 111191111.
%Y A077795 Cf. A004023, A077775-A077798, A107123-A107127, A107648, A107649, A115073, A183174-A183187.
%K A077795 more,nonn,base
%O A077795 1,1
%A A077795 _Patrick De Geest_, Nov 16 2002
%E A077795 Name corrected by _Jon E. Schoenfield_, Oct 30 2018
%E A077795 a(8)-a(9) from _Robert Price_, Jan 30 2025