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A029730 Numbers that are palindromic in base 16. 10
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 17, 34, 51, 68, 85, 102, 119, 136, 153, 170, 187, 204, 221, 238, 255, 257, 273, 289, 305, 321, 337, 353, 369, 385, 401, 417, 433, 449, 465, 481, 497, 514, 530, 546, 562, 578, 594, 610, 626, 642 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,3
LINKS
Phakhinkon Phunphayap and Prapanpong Pongsriiam, Estimates for the Reciprocal Sum of b-adic Palindromes, 2019.
Eric Weisstein's World of Mathematics, Palindromic Number.
Eric Weisstein's World of Mathematics, Hexadecimal.
Wikipedia, Palindromic number.
Wikipedia, Hexadecimal.
FORMULA
Sum_{n>=2} 1/a(n) = 3.71109616... (Phunphayap and Pongsriiam, 2019). - Amiram Eldar, Oct 17 2020
EXAMPLE
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F, 11, 22, 33, 44, 55, 66, 77, 88, 99, AA, BB, CC, DD, EE, FF, 101, 111, 121, 131, 141, 151, 161, 171, 181, 191,1A1, 1B1, 1C1, 1D1, 1E1, 1F1, 202, 212, 222, 232, 242, 252, 262, 272, 282, 292, 2A2, 2B2, 2C2, 2D2, 2E2, 2F2, 303, 313, 323, 333, 343, 353, 363, 373, 383, 393, 3A3, 3B3, 3C3, 3D3, 3E3, 3F3, 404, ... - Reinhard Zumkeller, Sep 23 2015
MATHEMATICA
palindromicQ[n_, b_] := Module[{i = IntegerDigits[n, b]}, i == Reverse[i]]; Select[Range[1000], palindromicQ[#, 16] &] (* Vladimir Joseph Stephan Orlovsky, Jul 08 2009 *)
PROG
(Haskell)
a029730 n = a029730_list !! (n-1)
a029730_list = map (foldr (\h v -> 16 * v + h) 0) $
filter (\xs -> xs == reverse xs) a262437_tabf
-- Reinhard Zumkeller, Sep 23 2015
(PARI) isok(n) = my(v=digits(n, 16)); v == Vecrev(v); \\ Michel Marcus, Sep 30 2018
CROSSREFS
Cf. A029731 (also palindromic in decimal), A056962, A262437.
Sequence in context: A048313 A043719 A296759 * A297289 A048327 A048340
KEYWORD
nonn,base
AUTHOR
STATUS
approved

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Last modified April 13 17:26 EDT 2024. Contains 371644 sequences. (Running on oeis4.)