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%I #20 Aug 18 2015 12:57:29
%S 0,1,2,4,8,16,40,100,121,142,164,242,328,400,1312,8200,9103,14762,
%T 54008,76024,108016,112048,233920,532900,639721,741586,2585488,
%U 3316520,11502842,24919360,35664908,87001616,184827640,4346524576,5642510512,11641189600,65304259157,68095147754,469837033600,830172165614,17136683996456,21772277941544,22666883572232,45221839119556
%N Palindromic numbers in bases 3 and 7 written in base 10.
%H Giovanni Resta, <a href="/A259377/b259377.txt">Table of n, a(n) for n = 1..72</a>
%H <a href="/index/Pac#palindromes">Index entries for sequences related to palindromes</a>
%F Intersection of A014190 and A029954.
%e 142 is in the sequence because 142_10 = 262_7 = 12021_3.
%t (* first load nthPalindromeBase from A002113 *) palQ[n_Integer, base_Integer] := Block[{}, Reverse[ idn = IntegerDigits[n, base]] == idn]; k = 0; lst = {}; While[k < 21000000, pp = nthPalindromeBase[k, 7]; If[palQ[pp, 3], AppendTo[lst, pp]; Print[pp]]; k++]; lst
%t b1=3; b2=7; lst={};Do[d1=IntegerDigits[n, b1]; d2=IntegerDigits[n, b2]; If[d1==Reverse[d1] && d2==Reverse[d2], AppendTo[lst, n]], {n, 0, 10000000}]; lst (* _Vincenzo Librandi_, Jul 17 2015 *)
%Y Cf. A007632, A007633, A029731, A029804, A029961, A029962, A029963, A029964, A029965, A029966, A029967, A029968, A029969, A029970, A048268, A060792, A097855, A097856, A097928, A097929, A097930, A097931, A099145, A099146, A099165, A182232, A182233, A182234, A250408, A250409, A250410, A250411, A250412, A259374, A259375, A259376, A259377, A259378, A249156, A259380, A259381, A259382, A259383, A259384, A259385, A259386, A259387, A259388, A259389, A259390.
%K nonn,base
%O 1,3
%A Eric A. Schmidt and _Robert G. Wilson v_, Jul 16 2015