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A260254 Number of ways to write n as sum of two palindromes in decimal representation. 9
1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 5, 5, 5, 4, 4, 3, 3, 2, 2, 1, 1, 0, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 4, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 4, 1, 1, 1, 1, 1, 1, 1, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

a(A035137(n)) = 0; a(A260255(n)) > 0.

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 0..10000

Hugo Pfoertner, Plot of first 10^6 terms

Hugo Pfoertner, Plot of first 3*10^7 terms

FORMULA

a(n) = sum{A136522(n - A002113(k)): k = 1..floor(n/2)}.

EXAMPLE

.   n | a(n) |                                n | a(n) |

. ----+------+--------------------------    ----+------+--------------

.   0 |    1 |  0                            21 |    0 |  ./.

.   1 |    1 |  1                            22 |    2 |  22, 11+11

.   2 |    2 |  2, 1+1                       23 |    1 |  22+1

.   3 |    2 |  3, 2+1                       24 |    1 |  22+2

.   4 |    3 |  4, 3+1, 2+2                  25 |    1 |  22+3

.   5 |    3 |  5, 4+1, 3+2                  26 |    1 |  22+4

.   6 |    4 |  6, 5+1, 4+2, 3+3             27 |    1 |  22+5

.   7 |    4 |  7, 6+1, 5+2, 4+3             28 |    1 |  22+6

.   8 |    5 |  8, 7+1, 6+2, 5+3, 4+4        29 |    1 |  22+7

.   9 |    5 |  9, 8+1, 7+2, 6+3, 5+4        30 |    1 |  22+8

.  10 |    5 |  9+1, 8+2, 7+3, 6+4, 5+5      31 |    1 |  22+9

.  11 |    5 |  11, 9+2, 8+3, 7+4, 6+5       32 |    0 |  ./.

.  12 |    5 |  11+1, 9+3, 8+4, 7+5, 6+6     33 |    2 |  33, 22+11

.  13 |    4 |  11+2, 9+4, 8+5, 7+6          34 |    1 |  33+1

.  14 |    4 |  11+3, 9+5, 8+6, 7+7          35 |    1 |  33+2

.  15 |    3 |  11+4, 9+6, 8+7               36 |    1 |  33+3

.  16 |    3 |  11+5, 9+7, 8+8               37 |    1 |  33+4

.  17 |    2 |  11+6, 9+8                    38 |    1 |  33+5

.  18 |    2 |  11+7, 9+9                    39 |    1 |  33+6

.  19 |    1 |  11+8                         40 |    1 |  33+7

.  20 |    1 |  11+9                         41 |    1 |  33+8  .

PROG

(Haskell)

a260254 n = sum $ map (a136522 . (n -)) $

               takeWhile (<= n `div` 2) a002113_list

CROSSREFS

Cf. A002113, A136522, A035137, A260255.

Sequence in context: A140828 A262907 A290323 * A282711 A035100 A085089

Adjacent sequences:  A260251 A260252 A260253 * A260255 A260256 A260257

KEYWORD

nonn,base,look

AUTHOR

Reinhard Zumkeller, Jul 21 2015

STATUS

approved

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Last modified February 20 10:10 EST 2018. Contains 299384 sequences. (Running on oeis4.)