cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A372779 Numbers m such that v^n - u^m < u^(m+1) - v^n, where u=2, v=3, and u^m < v^n < u^(m+1).

Original entry on oeis.org

2, 4, 6, 7, 9, 11, 12, 14, 16, 18, 19, 21, 23, 24, 26, 28, 30, 31, 33, 35, 36, 38, 40, 42, 43, 45, 47, 48, 50, 52, 53, 55, 57, 59, 60, 62, 64, 65, 67, 69, 71, 72, 74, 76, 77, 79, 81, 83, 84, 86, 88, 89, 91, 93, 95, 96, 98, 100, 101, 103, 105, 106, 108, 110
Offset: 1

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Author

Clark Kimberling, May 18 2024

Keywords

Examples

			The condition u^m < v^n < u^(m + 1) implies m = floor (n*log(v)/log(u)). With u=2 and v=3, for n = 1, we have m = 1 and 3 - 2 >= 4 - 3, so 1 is in A372780. For n = 2, we have m = 3 and 9 - 8 < 16 - 9, so 2 is in this sequence.
		

Crossrefs

Cf. A000079, A000244, A056576, A372780 (complement).

Programs

  • Mathematica
    z = 200; {u, v} = {2, 3};
    m[n_] := Floor[n*Log[v]/Log[u]];
    Table[m[n], {n, 0, z}];
    s = Select[Range[z], v^# - u^m[#] < u^(m[#] + 1) - v^# &]  (* this sequence *)
    Complement[Range[Max[s]], s]   (* A372780 *)