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A290303 Values of usigma(n) = usigma(n+1). 2
24, 60, 72, 180, 1440, 2160, 1872, 2640, 2400, 3000, 2880, 3024, 4320, 4320, 4320, 5280, 5280, 7400, 8640, 10080, 10200, 11520, 11880, 11520, 11088, 12960, 12096, 14400, 25920, 21600, 26640, 34560, 25200, 40320, 34560, 36000, 51840, 60480, 63360, 60480, 65280 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The sum of unitary divisors of numbers n such that n and n+1 have the same sum.

The unitary version of A053215.

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000

FORMULA

a(n) = A034448(A064125(n)).

MATHEMATICA

usigma[n_] := Block[{d = Divisors[n]}, Plus @@ Select[d, GCD[ #, n/# ] == 1 &]]; a={}; u1=0; For[k=0, k<10^5, k++; u2=usigma[k]; If[u1==u2, a = AppendTo[a, u1]]; u1=u2]; a

CROSSREFS

Cf. A002961, A034448, A053215, A064125.

Sequence in context: A190104 A255968 A211325 * A044126 A044507 A101860

Adjacent sequences:  A290300 A290301 A290302 * A290304 A290305 A290306

KEYWORD

nonn

AUTHOR

Amiram Eldar, Jul 26 2017

STATUS

approved

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Last modified October 20 10:45 EDT 2019. Contains 328257 sequences. (Running on oeis4.)