%I #15 Feb 24 2017 17:59:05
%S 0,0,0,0,0,0,1,6,21,56,126,246,432,702,1077,1576,2232,3072,4112,5352,
%T 6801,8422,10197,12102,14117,16146,18177,20112,21882,23382,24661,
%U 25566,26136,26316,26181,25560,24677,23436,21981,20226,18486,16536,14642,12702,10962,9166,7662,6222,5042,3912,3096,2306,1746,1236,921,600
%N Number of ways to write n as an ordered sum of 6 prime power palindromes (A084092).
%C Is there k which satisfies a(n) > 0 for all n > k?
%H Ilya Gutkovskiy, <a href="/A282845/a282845.pdf">Extended graphical example</a>
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/PrimePower.html">Prime Power</a>
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/PalindromicNumber.html">Palindromic Number</a>
%H <a href="/index/Pac#palindromes">Index entries for sequences related to palindromes</a>
%F G.f.: (Sum_{k>=1} x^A084092(k))^6.
%e a(7) = 6 because we have:
%e [2, 1, 1, 1, 1, 1]
%e [1, 2, 1, 1, 1, 1]
%e [1, 1, 2, 1, 1, 1]
%e [1, 1, 1, 2, 1, 1]
%e [1, 1, 1, 1, 2, 1]
%e [1, 1, 1, 1, 1, 2]
%t nmax = 55; CoefficientList[Series[(x + Sum[Boole[PrimePowerQ[k] && PalindromeQ[k]] x^k, {k, 1, nmax}])^6, {x, 0, nmax}], x]
%Y Cf. A000961, A002113, A002385, A084092, A260254, A261131, A261132, A261422, A282585.
%K base,nonn
%O 0,8
%A _Ilya Gutkovskiy_, Feb 22 2017