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.

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A346377 a(n) is the number of solutions k to A075254(k) = n.

Original entry on oeis.org

1, 0, 0, 1, 0, 1, 0, 1, 0, 1, 1, 0, 0, 2, 1, 0, 1, 0, 1, 0, 0, 1, 2, 1, 0, 2, 0, 0, 1, 0, 1, 0, 1, 1, 2, 1, 0, 1, 1, 1, 1, 1, 0, 0, 0, 2, 2, 0, 0, 0, 1, 0, 1, 1, 1, 1, 0, 1, 3, 0, 0, 2, 1, 0, 1, 0, 0, 0, 2, 0, 3, 1, 0, 1, 0, 2, 0, 0, 1, 0, 0, 2, 1, 2, 0, 1, 0, 1, 2, 0, 0, 0, 2, 1, 3, 1, 0, 1, 1
Offset: 1

Views

Author

J. M. Bergot and Robert Israel, Jul 14 2021

Keywords

Comments

a(n) is the number of k such that k + A001414(k) = n.

Examples

			a(14) = 2 because there are two solutions to A075254(k) = 14, namely
A075254(7) = 7+7 = 14
A075254(8) = 8+2+2+2 = 14
		

Crossrefs

Programs

  • Maple
    f:= proc(n) local t; add(t[1]*t[2],t=ifactors(n)[2])+n end proc:
    N:= 100: # for a(1)..a(N)
    V:= Vector(N):
    for n from 1 to N do
      v:= f(n);
      if v <= N then V[v]:= V[v]+1 fi
    od:
    convert(V[1..N],list);
  • Mathematica
    f[1] = 1; f[n_] := n + Plus @@ Times @@@ FactorInteger[n]; m = 100; v = Table[0, {m}]; Do[i = f[n]; If[i <= m, v[[i]]++], {n, 1, m}]; v (* Amiram Eldar, Jul 14 2021 *)
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