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 A029954 Palindromic in base 7. 26
 0, 1, 2, 3, 4, 5, 6, 8, 16, 24, 32, 40, 48, 50, 57, 64, 71, 78, 85, 92, 100, 107, 114, 121, 128, 135, 142, 150, 157, 164, 171, 178, 185, 192, 200, 207, 214, 221, 228, 235, 242, 250, 257, 264, 271, 278, 285, 292, 300, 307, 314, 321, 328, 335, 342, 344, 400, 456 (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) = 3.1313768... (Phunphayap and Pongsriiam, 2019). - Amiram Eldar, Oct 17 2020 MATHEMATICA f[n_, b_] := Module[{i=IntegerDigits[n, b]}, i==Reverse[i]]; lst={}; Do[If[f[n, 7], AppendTo[lst, n]], {n, 1000}]; lst (* Vladimir Joseph Stephan Orlovsky, Jul 08 2009 *) pal7Q[n_]:=Module[{idn7=IntegerDigits[n, 7]}, idn7==Reverse[idn7]]; Select[ Range[0, 500], pal7Q] (* Harvey P. Dale, Jul 30 2015 *) PROG (Python) from gmpy2 import digits def palQgen(l, b): # generator of palindromes in base b of length <= 2*l     if l > 0:         yield 0         for x in range(1, l+1):             for y in range(b**(x-1), b**x):                 s = digits(y, b)                 yield int(s+s[-2::-1], b)             for y in range(b**(x-1), b**x):                 s = digits(y, b)                 yield int(s+s[::-1], b) A029954_list = list(palQgen(4, 7)) # Chai Wah Wu, Dec 01 2014 (PARI) ispal(n, b=7)=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. Sequence in context: A043710 A296703 A297262 * A048318 A037402 A048332 Adjacent sequences:  A029951 A029952 A029953 * A029955 A029956 A029957 KEYWORD nonn,base,easy,changed AUTHOR STATUS approved

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Last modified October 22 10:18 EDT 2020. Contains 337950 sequences. (Running on oeis4.)