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A356452
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Even numbers k such that k^2 is not in A014567; complement of A356448 in the even numbers.
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4
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14, 42, 70, 78, 84, 98, 112, 114, 124, 126, 154, 156, 168, 182, 186, 198, 210, 222, 228, 234, 238, 252, 258, 266, 294, 308, 310, 312, 322, 336, 342, 350, 366, 372, 378, 390, 396, 402, 406, 418, 420, 434, 438, 444, 456, 462, 468, 474, 490, 504, 516, 518, 532, 546, 550, 558
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OFFSET
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1,1
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COMMENTS
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Even numbers k such that k and sigma(k^2) are not coprime, sigma = A000203.
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LINKS
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FORMULA
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EXAMPLE
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14 is a term since 14 and sigma(14^2) = 399 have a common factor 7.
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MATHEMATICA
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Select[2 Range[300], !CoprimeQ[#, DivisorSigma[1, #^2]]&] (* Harvey P. Dale, Mar 09 2023 *)
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PROG
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(PARI) isA356452(n) = !(n%2) && gcd(n, sigma(n^2))>1
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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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