%I #16 Jun 26 2024 21:54:50
%S 2,3002003,3303002003033,9303303002003033039,
%T 7609303303002003033039067,3007609303303002003033039067003,
%U 9003007609303303002003033039067003009,3819003007609303303002003033039067003009183
%N Palindromic prime pyramid with a(1)=2 such that (number of digits in a(n+1)) = (number of digits in a(n)) + 6.
%C G. L. Honaker Jr. and C. Caldwell conjectured that this pyramid has a finite number of terms (about 193 terms).
%C This pyramid is only an example of such a pyramid and is not the least possible (because otherwise we would have a(2)=102201), nor is it the tallest known pyramid expanding by 6 digits at each step (see Rivera link).  _Sean A. Irvine_, Jun 26 2024
%D G. L. Honaker Jr. and C. Caldwell, Palindromic prime pyramids. J.Recreational mathematics, vol. 30.3, pp. 169176,19992000
%D J.P. Delahaye, "Pour la science", (French edition of Scientific American), Juin 2002, p. 99
%H C. Rivera, <a href="http://www.primepuzzles.net/puzzles/puzz_1143.htm">Puzzle 1143, Problems & Puzzles</a>
%Y Cf. A070927, A070922.
%K easy,nonn,base
%O 1,1
%A _Benoit Cloitre_, May 26 2002
