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A076872
a(n) = number of numbers <= n that are the sum of two squarefull numbers.
2
0, 1, 1, 1, 2, 2, 2, 3, 4, 5, 5, 6, 7, 7, 7, 8, 9, 10, 10, 11, 11, 11, 11, 12, 13, 14, 14, 15, 16, 16, 17, 18, 19, 20, 21, 22, 23, 23, 23, 24, 25, 25, 26, 27, 28, 28, 28, 29, 29, 30, 30, 31, 32, 33, 33, 33, 34, 35, 36, 36, 37, 37, 38, 39, 40, 40, 40, 41, 41, 41, 41, 42, 43, 44, 44
OFFSET
1,5
REFERENCES
Aleksandar Ivić, The Riemann Zeta-Function, Wiley, NY, 1985, see p. 439.
LINKS
MATHEMATICA
With[{m = 120}, pow = Select[Range[m], # == 1 || Min[FactorInteger[#][[;; , 2]]] > 1 &]; Accumulate @ BinCounts[Select[Union[Plus @@@ Tuples[pow, {2}]], # <= m &], {1, m, 1}]] (* Amiram Eldar, Feb 12 2023 *)
CROSSREFS
Sequence in context: A230413 A029096 A194820 * A008906 A029074 A258741
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Nov 25 2002
EXTENSIONS
More terms from Vladeta Jovovic, Nov 26 2002
STATUS
approved