

A261131


Number of ways to write n as the sum of 3 positive palindromes.


4



0, 0, 0, 1, 1, 2, 3, 4, 5, 7, 8, 10, 11, 13, 13, 15, 14, 15, 14, 14, 12, 12, 9, 9, 8, 7, 6, 6, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 5, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 5, 8, 7, 7, 7, 7, 7
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OFFSET

0,6


COMMENTS

Conjecture: a(n) > 0 for n > 2, i.e., every number greater than 2 can be written as the sum of 3 positive palindromes.


LINKS

Giovanni Resta, Table of n, a(n) for n = 0..10000


EXAMPLE

a(28) = 5 since 28 can be expressed in 5 ways as the sum of 3 positive palindromes, namely, 28 = 22+5+1 = 22+4+2 = 22+3+3 = 11+11+6 = 11+9+8.


MATHEMATICA

pal=Select[Range@ 1000, (d = IntegerDigits@ #; d == Reverse@ d)&]; a[n_] := Length@ IntegerPartitions[n, {3}, pal]; a /@ Range[0, 1000]


CROSSREFS

Cf. A002113, A260254, A261132.
Sequence in context: A047503 A228803 A037014 * A225061 A133223 A065003
Adjacent sequences: A261128 A261129 A261130 * A261132 A261133 A261134


KEYWORD

nonn,base,look


AUTHOR

Giovanni Resta, Aug 10 2015


STATUS

approved



