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A358484 Numbers k such that k, k+1 and k+2 are all bi-unitary abundant numbers (A292982). 1
268005374, 600350750, 2666847104, 2683146464, 2695309694, 2849458688, 3904592768, 4112553248, 5368737374, 6554410784, 6955574624, 8207456894, 8967010688, 9220179968, 9868366430, 10529171288, 12147283070, 12411630944, 12491149670, 13911605630, 14126720894, 14396391008 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..1546 (terms below 10^12)
EXAMPLE
268005374 is in the sequence since 268005374, 268005375 and 268005376 are all bi-unitary abundant numbers (A292982): bsigma(268005374) = 568995840 > 2 * 268005374, bsigma(268005375) = 540633600 > 2 * 268005375, and bsigma(268005376) = 541258200 > 2 * 268005376 (bsigma is the sum of bi-unitary divisors, A188999).
MATHEMATICA
f[p_, e_] := (p^(e + 1) - 1)/(p - 1) - If[OddQ[e], 0, p^(e/2)]; bsigma[1] = 1; bsigma[n_] := Times @@ f @@@ FactorInteger[n]; abQ[n_] := bsigma[n] > 2*n; v = Cases[Import["https://oeis.org/A096536/b096536.txt", "Table"], {_, _}][[;; , 2]]; Select[v, And @@ abQ /@ (# + {0, 1, 2}) &]
CROSSREFS
Subsequence of A096536, A292982 and A318167.
Cf. A188999.
Sequence in context: A125576 A233501 A295477 * A011578 A223605 A223698
KEYWORD
nonn
AUTHOR
Amiram Eldar, Nov 18 2022
STATUS
approved

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Last modified July 20 23:17 EDT 2024. Contains 374461 sequences. (Running on oeis4.)