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A124334 Nonpalindromes in base 10 that are palindromes in base 2. 1
15, 17, 21, 27, 31, 45, 51, 63, 65, 73, 85, 93, 107, 119, 127, 129, 153, 165, 189, 195, 219, 231, 255, 257, 273, 297, 325, 341, 365, 381, 387, 403, 427, 443, 455, 471, 495, 511, 513, 561, 633, 645, 693, 765, 771, 819, 843, 891, 903, 951, 975 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Robert Israel, Table of n, a(n) for n = 1..10000

EXAMPLE

17(10) = 10001(2), a palindrome.

MAPLE

N:= 10000: # to get the first N entries

count:= 0:

for d from 1 while count < N do

   d1:= ceil(d/2); d2:= d - d1;

   for x from 2^(d1-1) to 2^d1 - 1 while count < N do

      if d::even then x1:= x else x1 := floor(x/2) fi;

      L:= convert(x1, base, 2);

      y:= 2^(d2)*x + add(L[j]*2^(d2-j), j=1..d2);

      L10:= convert(y, base, 10);

      if ListTools[Reverse](L10) = L10 then next fi;

      count:= count+1;

      A[count]:= y;

   od

od:

seq(A[n], n=1..N);

# Robert Israel, Apr 20 2014

MATHEMATICA

Select[Range[1000], Reverse[IntegerDigits[ # ]] != IntegerDigits[ # ] && Reverse[IntegerDigits[ #, 2]] == IntegerDigits[ #, 2] &]

CROSSREFS

Cf. A007632 = numbers that are palindromic in bases 2 and 10.

Sequence in context: A074748 A183981 A155111 * A002155 A290749 A091017

Adjacent sequences:  A124331 A124332 A124333 * A124335 A124336 A124337

KEYWORD

base,nonn

AUTHOR

Tanya Khovanova, Dec 26 2006

STATUS

approved

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Last modified August 24 02:32 EDT 2017. Contains 291052 sequences.