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A343819
Numbers k such that k and k+1 have the same number of Fermi-Dirac factors (A064547).
11
2, 3, 4, 14, 16, 20, 21, 26, 27, 32, 33, 34, 35, 38, 44, 45, 50, 51, 57, 62, 63, 64, 68, 74, 75, 76, 85, 86, 91, 92, 93, 94, 98, 99, 104, 111, 115, 116, 117, 118, 122, 123, 124, 133, 135, 141, 142, 143, 144, 145, 146, 147, 158, 161, 171, 175, 176, 177, 187, 189
OFFSET
1,1
COMMENTS
Since the number of infinitary divisors of k is A037445(k) = 2^A064547(k), this is also the sequence of numbers k such that k and k+1 have the same number of infinitary divisors.
LINKS
EXAMPLE
2 is a term since A064547(2) = A064547(3) = 1.
MATHEMATICA
fd[1] = 0; fd[n_] := Plus @@ DigitCount[FactorInteger[n][[;; , 2]], 2, 1]; Select[Range[200], fd[#] == fd[# + 1] &]
CROSSREFS
Similar sequences: A005237, A006049.
Subsequence of A086263.
Sequence in context: A354075 A344313 A103048 * A140128 A167906 A100998
KEYWORD
nonn
AUTHOR
Amiram Eldar, Apr 30 2021
STATUS
approved