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 A275254 The bi-unitary gcd-sum function. 2
 1, 3, 5, 7, 9, 14, 13, 15, 17, 25, 21, 30, 25, 36, 43, 31, 33, 47, 37, 57, 61, 58, 45, 64, 49, 69, 53, 82, 57, 108, 61, 63, 99, 91, 113, 99, 73, 102, 117, 117, 81, 163, 85, 132, 141, 124, 93, 130, 97, 135, 155, 157, 105, 146, 181 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Row sums of A165430. LINKS Amiram Eldar, Table of n, a(n) for n = 1..10000 L. Toth, On the Bi-Unitary Analogues of Euler's Arithmetical Function and the Gcd-Sum Function, JIS 12 (2009) 09.5.2, function P**(n). FORMULA a(n) = Sum_{k=1..n} A165430(n,k). MAPLE Pstarstar := proc(n) add(A165430(k, n), k=1..n) ; end proc: MATHEMATICA phi[x_, n_] := Sum[Boole[GCD[k, n] == 1], {k, 1, x}]; uphi[1]=1; uphi[n_] := Times @@ (-1 + Power @@@ FactorInteger[n]); a[n_] := DivisorSum[n, uphi[#] * phi[n/#, #] &, GCD[#, n/#] == 1 &]; Array[a, 100] (* Amiram Eldar, Sep 09 2019 *) CROSSREFS Cf. A165430. Sequence in context: A107220 A249412 A098758 * A029608 A211135 A145388 Adjacent sequences: A275251 A275252 A275253 * A275255 A275256 A275257 KEYWORD nonn AUTHOR R. J. Mathar, Jul 21 2016 STATUS approved

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Last modified December 5 02:30 EST 2022. Contains 358572 sequences. (Running on oeis4.)