A046486 Numbers k such that the sum of the first k palindromes is a palindrome.

1, 2, 3, 12, 16, 47, 314

Offset: 1

Author

Patrick De Geest, Sep 15 1998

Keywords

• nonn
• hard
• base

Examples

			a(n)=47 so 1+2+3+...+373+383 (47 terms) = 7557.
		

Links

• Patrick De Geest, World!Of Numbers

Crossrefs

Cf. A002113, A046487, A046488.

Programs

Mathematica

palQ[n_] := Reverse[x = IntegerDigits[n]] == x; t = Select[Range[25000], palQ[#] &]; Flatten[Rest[Position[Accumulate[t], ?palQ]]] (* _Jayanta Basu, Jun 26 2013 *)
Position[Accumulate[Select[Range[100000],PalindromeQ]],?PalindromeQ] // Flatten (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale, Jan 31 2020 *)