|
%I #12 Apr 03 2023 10:36:09
%S 2,30203,133020331,1713302033171,12171330203317121,
%T 151217133020331712151,1815121713302033171215181,
%U 16181512171330203317121518161,331618151217133020331712151816133,9333161815121713302033171215181613339,11933316181512171330203317121518161333911
%N a(n+1) is the smallest palindromic prime containing exactly 2 more digits on each end than the previous term, with a(n) as a central substring.
%D Pickover, Clifford A., A Passion for Mathematics: Numbers, Puzzles, Madness, Religion and the Quest for Reality, John Wiley & Sons, Inc., Hoboken, New Jersey (2005) p. 108.
%H C. K. Caldwell, <a href="https://t5k.org/glossary/page.php?sort=PalindromicPrime">Palindromic Primes</a>
%t cc=If[EvenQ[First[#]],Reverse[#],#]&/@Tuples[{Range[0,9],Range[1,9,2]}]; nxt[n_]:=First[Select[Sort[FromDigits[Flatten[Join[{#,IntegerDigits[ n], Reverse[#]}]]]&/@cc],PrimeQ]]; NestList[nxt,2,10] (* _Harvey P. Dale_, Dec 24 2012 *)
%Y Cf. A053600.
%K base,fini,full,nice,nonn
%O 1,1
%A _G. L. Honaker, Jr._, Jan 26 2000
|
