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A282845
Number of ways to write n as an ordered sum of 6 prime power palindromes (A084092).
1
0, 0, 0, 0, 0, 0, 1, 6, 21, 56, 126, 246, 432, 702, 1077, 1576, 2232, 3072, 4112, 5352, 6801, 8422, 10197, 12102, 14117, 16146, 18177, 20112, 21882, 23382, 24661, 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
OFFSET
0,8
COMMENTS
Is there k which satisfies a(n) > 0 for all n > k?
LINKS
Eric Weisstein's World of Mathematics, Prime Power
Eric Weisstein's World of Mathematics, Palindromic Number
FORMULA
G.f.: (Sum_{k>=1} x^A084092(k))^6.
EXAMPLE
a(7) = 6 because we have:
[2, 1, 1, 1, 1, 1]
[1, 2, 1, 1, 1, 1]
[1, 1, 2, 1, 1, 1]
[1, 1, 1, 2, 1, 1]
[1, 1, 1, 1, 2, 1]
[1, 1, 1, 1, 1, 2]
MATHEMATICA
nmax = 55; CoefficientList[Series[(x + Sum[Boole[PrimePowerQ[k] && PalindromeQ[k]] x^k, {k, 1, nmax}])^6, {x, 0, nmax}], x]
KEYWORD
base,nonn
AUTHOR
Ilya Gutkovskiy, Feb 22 2017
STATUS
approved