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A033457
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GCD-convolution of squares A000290 with themselves.
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2
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1, 2, 6, 4, 19, 6, 28, 24, 45, 10, 98, 12, 79, 94, 120, 16, 201, 18, 238, 164, 171, 22, 436, 120, 229, 234, 426, 28, 695, 30, 496, 352, 369, 370, 1014, 36, 451, 470, 1068, 40, 1261, 42, 946, 1020, 639, 46, 1832, 336
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OFFSET
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0,2
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LINKS
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FORMULA
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MATHEMATICA
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Table[Sum[d^2*EulerPhi[(n + 2)/d], {d, Most@ Divisors[n + 2]}], {n, 0, 47}] (* Michael De Vlieger, Mar 20 2015 *)
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PROG
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(Sage) sum([d^2*euler_phi(int((n+2)/d)) for d in range(1, n+2) if (n+2)%d==0]) # Danny Rorabaugh, Mar 20 2015
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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