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 A335140 Unitary pseudoperfect numbers (A293188) that are nonsquarefree. 2
 60, 90, 150, 294, 420, 630, 660, 726, 750, 780, 840, 924, 990, 1014, 1020, 1050, 1092, 1140, 1170, 1380, 1386, 1428, 1470, 1530, 1596, 1638, 1650, 1710, 1734, 1740, 1860, 1890, 1950, 2058, 2070, 2142, 2166, 2220, 2394, 2460, 2550, 2580, 2610, 2790, 2820, 2850 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS The pseudoperfect numbers (A005835) that are squarefree are also unitary pseudoperfect numbers (A293188) since all of their divisors are unitary. LINKS EXAMPLE 60 is a term since it is nonsquarefree (it is divisible by 4 = 2^2) and it is equal to a sum of its aliquot unitary divisors: 1 + 3 + 4 + 5 + 12 + 15 + 20 = 60. MATHEMATICA pspQ[n_] := !SquareFreeQ[n] && Module[{d = Most @ Select[Divisors[n], CoprimeQ[#, n/#] &], x}, Plus @@ d >= n && SeriesCoefficient[Series[Product[1 + x^d[[i]], {i, Length[d]}], {x, 0, n}], n] > 0]; Select[Range[1000], pspQ] CROSSREFS Intersection of A013929 and A293188. Subsequence of A005835. Sequence in context: A100659 A069976 A110546 * A335201 A267434 A048934 Adjacent sequences:  A335136 A335137 A335138 * A335141 A335142 A335143 KEYWORD nonn AUTHOR Amiram Eldar, May 25 2020 STATUS approved

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Last modified August 6 09:38 EDT 2020. Contains 336245 sequences. (Running on oeis4.)