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 A029952 Palindromic in base 5. 27
 0, 1, 2, 3, 4, 6, 12, 18, 24, 26, 31, 36, 41, 46, 52, 57, 62, 67, 72, 78, 83, 88, 93, 98, 104, 109, 114, 119, 124, 126, 156, 186, 216, 246, 252, 282, 312, 342, 372, 378, 408, 438, 468, 498, 504, 534, 564, 594, 624, 626, 651, 676, 701, 726, 756, 781, 806, 831 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS Cilleruelo, Luca, & Baxter prove that this sequence is an additive basis of order (exactly) 3. - Charles R Greathouse IV, May 03 2020 LINKS T. D. Noe, Table of n, a(n) for n = 1..10000 Javier Cilleruelo, Florian Luca and Lewis Baxter, Every positive integer is a sum of three palindromes, Mathematics of Computation, Vol. 87, No. 314 (2018), pp. 3023-3055, arXiv preprint, arXiv:1602.06208 [math.NT], 2017. Patrick De Geest, Palindromic numbers beyond base 10. Phakhinkon Phunphayap and Prapanpong Pongsriiam, Estimates for the Reciprocal Sum of b-adic Palindromes, 2019. FORMULA Sum_{n>=2} 1/a(n) = 2.9200482... (Phunphayap and Pongsriiam, 2019). - Amiram Eldar, Oct 17 2020 MAPLE # test for palindrome in base b, from N. J. A. Sloane, Sep 13 2015 b:=5; ispal := proc(n) global b; local t1, t2, i; if n <= b-1 then return(1); fi; t1:=convert(n, base, b); t2:=nops(t1); for i from 1 to floor(t2/2) do if t1[i] <> t1[t2+1-1] then return(-1); fi; od: return(1); end; lis:=[]; for n from 0 to 100 do if ispal(n) = 1 then lis:=[op(lis), n]; fi; od: lis; MATHEMATICA f[n_, b_] := Module[{i=IntegerDigits[n, b]}, i==Reverse[i]]; lst={}; Do[If[f[n, 5], AppendTo[lst, n]], {n, 1000}]; lst (* Vladimir Joseph Stephan Orlovsky, Jul 08 2009 *) PROG (MAGMA) [n: n in [0..900] | Intseq(n, 5) eq Reverse(Intseq(n, 5))]; // Vincenzo Librandi, Sep 09 2015 (PARI) ispal(n, b=5)=my(d=digits(n, b)); d==Vecrev(d) \\ Charles R Greathouse IV, May 03 2020 CROSSREFS Palindromes in bases 2 through 10: A006995, A014190, A014192, A029952, A029953, A029954, A029803, A029955, A002113. Cf. A261917, A261918. Sequence in context: A043708 A296697 A297256 * A140494 A048316 A037393 Adjacent sequences:  A029949 A029950 A029951 * A029953 A029954 A029955 KEYWORD nonn,base,easy,changed AUTHOR STATUS approved

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Last modified October 24 04:47 EDT 2020. Contains 337975 sequences. (Running on oeis4.)