A115336 a(n) is the smallest number representable in exactly n ways as a sum of 2 palindromes (each of them >= 0).

0, 2, 4, 6, 8, 110, 353, 363, 373, 383, 393, 464, 474, 504, 484, 494, 575, 605, 585, 1049, 595, 767, 706, 686, 777, 696, 807, 787, 878, 13222, 797, 908, 888, 31812, 12892, 898, 989, 11220, 44444, 1201, 999, 28882, 11110, 42623, 30092, 1100, 11000, 36153

Offset

1,2

Links

Table of n, a(n) for n=1..48.

Example

a(6)=110 since 110=101+9=99+11=88+22=77+33=66+44=55+55 and no
number less than 110 has 6 such decompositions.

Mathematica

palQ[n_] := n == FromDigits@Reverse@IntegerDigits@n; pt = Select[Range[0, 50005], palQ]; t = Array[0&, 50000]; Do[v = pt[[i]]+pt[[j]]; If[v<50000, t[[v + 1]]++ ], {i, 600}, {j, i}]; Table[Position[t, k][[1, 1]]-1, {k, 55}]

Crossrefs

Cf. A035137, A115337.

Sequence in context: A085920 A228327 A081507 * A119666 A087302 A351777

Adjacent sequences: A115333 A115334 A115335 * A115337 A115338 A115339

Keyword

base,nonn

Author

Giovanni Resta, Jan 20 2006

Status

approved