login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

Numbers k such that the number of letters, excluding spaces and hyphens, in the English names of k and its reversal are the same.
1

%I #23 Oct 26 2024 22:57:34

%S 0,1,2,3,4,5,6,7,8,9,10,11,14,22,33,34,35,38,41,43,44,45,48,53,54,55,

%T 58,66,67,69,76,77,79,83,84,85,88,96,97,99,101,102,103,104,105,106,

%U 107,108,109,111,112,113,115,118,121,122,123,124,125,126,127,128,129

%N Numbers k such that the number of letters, excluding spaces and hyphens, in the English names of k and its reversal are the same.

%C All base-10 palindromes occur in this sequence.

%H Robert G. Wilson v, <a href="/A211408/b211408.txt">Table of n, a(n) for n = 0..23885</a>

%F {n such that A005589(n) = A005589(A004086(n))}.

%e 10 is in the sequence because "ten" has three letters, and so does "one" which is the name of the digital reverse of 10, which is 1 (because the leading 0 is truncated in 01).

%e 14 is in the sequence because "fourteen" and "fortyone" both have 8 letters.

%t lst= {(* copy the words from https://oeis.org/A000027/a000027.txt *)}; f[n_] := StringLength@ ToString@ lst[[n + 1]]; fQ[n_] := f@ n == f@ FromDigits@ Reverse@ IntegerDigits@ n; Select[Range[0, 130], fQ] (* _Robert G. Wilson v_, Feb 12 2013 *)

%Y Subsequences: A002113.

%Y Cf. A000027, A004086, A005589, A107322.

%K nonn,base,easy,word

%O 0,3

%A _Jonathan Vos Post_, Feb 09 2013

%E Corrected and extended by _Robert G. Wilson v_, Feb 12 2013