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 A297366 Numbers n such that uphi(n) + usigma(n) = uphi(n+1) + usigma(n+1), where uphi is the unitary totient function (A047994) and usigma the sum of unitary divisors (A034448). 0
 6, 10, 12, 15, 18, 22, 24, 26, 28, 36, 40, 46, 48, 52, 58, 63, 72, 80, 82, 88, 96, 100, 106, 108, 112, 124, 136, 148, 162, 166, 172, 178, 192, 196, 226, 232, 242, 250, 262, 268, 285, 288, 292, 316, 346, 352, 358, 382, 388, 400, 432, 448, 466, 478, 486, 502 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS The unitary version of A145749. LINKS EXAMPLE 6 is in the sequence since uphi(6) + usigma(6) = 2 + 12 = uphi(7) + usigma(7) = 6 + 8 = 14. MATHEMATICA usigma[n_] := If[n == 1, 1, Times @@ (1 + Power @@@ FactorInteger[n])]; uphi[n_] := (Times @@ (Table[#[[1]]^#[[2]] - 1, {1}] & /@ FactorInteger[n]))[[1]]; u[n_] := uphi[n]+usigma[n]; aQ[n_] := u[n] == u[n + 1]; Select[Range[10^3], aQ] CROSSREFS Cf. A034448, A047994, A145749. Sequence in context: A279550 A143958 A294278 * A325472 A305188 A270364 Adjacent sequences:  A297363 A297364 A297365 * A297367 A297368 A297369 KEYWORD nonn AUTHOR Amiram Eldar, Dec 29 2017 STATUS approved

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Last modified April 19 22:40 EDT 2021. Contains 343117 sequences. (Running on oeis4.)