The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation. Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A294029 Values of bsigma(k) = bsigma(k+1), where bsigma is the sum of the bi-unitary divisors (A188999). 1
 24, 40, 60, 720, 960, 1440, 2160, 2640, 2400, 3000, 4320, 4320, 4320, 5280, 7400, 11520, 11880, 12960, 14400, 20160, 30240, 26640, 34560, 25200, 34560, 49920, 51840, 60480, 63360, 60480, 65280, 62400, 61560, 115200, 93600, 114912, 100800, 120960, 120960 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS The sum of bi-unitary divisors of numbers n such that n and n+1 have the same sum (A293183). The bi-unitary version of A053215. LINKS Amiram Eldar, Table of n, a(n) for n = 1..2148 FORMULA a(n) = A188999(A293183(n)). EXAMPLE 24 is in the sequence since 24 = bsigma(14) = bsigma(15). MATHEMATICA f[n_] := Select[Divisors[n], Function[d, CoprimeQ[d, n/d]]]; bsigma[m_] := DivisorSum[m, # &, Last@Intersection[f@#, f[m/#]] == 1 &]; a = {}; b1 = 0; For[k = 0, k < 10^6, k++; b2 = bsigma[k]; If[b1 == b2, a = AppendTo[a, b1]]; b1 = b2]; a (* after Michael De Vlieger at A188999 *) CROSSREFS Cf. A053215, A290303, A188999, A293183. Sequence in context: A039296 A043899 A269452 * A195562 A026040 A259217 Adjacent sequences:  A294026 A294027 A294028 * A294030 A294031 A294032 KEYWORD nonn AUTHOR Amiram Eldar, Oct 22 2017 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified July 15 23:32 EDT 2020. Contains 335774 sequences. (Running on oeis4.)