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.

Showing 1-6 of 6 results.

A338495 Least number of hexagonal pyramidal numbers needed to represent n.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 1, 2, 3, 4, 5, 6, 7, 2, 3, 4, 5, 6, 7, 8, 3, 1, 2, 3, 4, 5, 6, 4, 2, 3, 4, 5, 6, 7, 5, 3, 4, 5, 6, 7, 8, 6, 4, 2, 3, 4, 5, 6, 7, 1, 2, 3, 4, 5, 6, 7, 2, 3, 4, 5, 6, 7, 8, 3, 4, 3, 4, 5, 6, 7, 4, 2, 3, 4, 5, 6, 7, 5, 3, 4, 5, 6, 7, 8, 6, 4, 5, 4, 5, 6, 7, 7, 5, 3, 1, 2, 3, 4, 5, 2, 3
Offset: 1

Views

Author

Ilya Gutkovskiy, Oct 30 2020

Keywords

Links

Crossrefs

Cf. A002412, A104246, A234533, A338479, A338493, A338494.

Programs

  • Maple
    N:= 200: # for a(1)..a(N)
V:= Vector(N):
S:= {seq(n*(n+1)*(4*n-1)/6,n=1..floor((N*3/2)^(1/3)))}:
V[convert(S,list)]:= 1:
T:= S:
for m from 2 do
  Tn:= select(`<=`,map(t -> op(t +~ S),T),N) minus T;
  if nops(Tn) = 0 then break fi;
  T:= T union Tn;
  V[convert(Tn,list)]:= m
od:
convert(V,list); # Robert Israel, Nov 02 2020

A338482 Least number of centered triangular numbers that sum to n.

Original entry on oeis.org

1, 2, 3, 1, 2, 3, 4, 2, 3, 1, 2, 3, 4, 2, 3, 4, 5, 3, 1, 2, 3, 4, 2, 3, 4, 5, 3, 4, 2, 3, 1, 2, 3, 4, 2, 3, 4, 2, 3, 4, 2, 3, 4, 5, 3, 1, 2, 3, 4, 2, 3, 4, 5, 3, 4, 2, 3, 4, 5, 3, 4, 2, 3, 1, 2, 3, 4, 2, 3, 4, 5, 3, 4, 2, 3, 4, 2, 3, 4, 5, 3, 4, 2, 3, 1, 2, 3, 4, 2, 3, 4, 2, 3, 4, 2, 3, 4, 5, 3, 4, 5
Offset: 1

Views

Author

Ilya Gutkovskiy, Oct 29 2020

Keywords

Comments

It appears that a(n) = 3 for n == 0 (mod 3), 1 <= a(n) <= 4 for n == 1 (mod 3), and 2 <= a(n) <= 5 for n == 2 (mod 3). - Robert Israel, Nov 13 2020

Links

Crossrefs

Cf. A005448, A061336, A101412, A104246, A234533, A338484.

Programs

  • Maple
    f:= proc(n) option remember; local r,i;
    r:= sqrt(24*n-15)/6+1/2;
    if r::integer then return 1 fi;
    1+min(seq(procname(n-(3*i*(i-1)/2+1)),i=1..floor(r)))
end proc:
map(f, [$1..200]); # Robert Israel, Nov 13 2020
  • Mathematica
    f[n_] := f[n] = Module[{r}, r = Sqrt[24n-15]/6+1/2; If[IntegerQ[r], Return[1]]; 1+Min[Table[f[n-(3i*(i-1)/2+1)], {i, 1, Floor[r]}]]];
Map[f, Range[200]] (* Jean-François Alcover, Sep 16 2022, after Robert Israel *)

A338484 Least number of centered square numbers needed to represent n.

Original entry on oeis.org

1, 2, 3, 4, 1, 2, 3, 4, 5, 2, 3, 4, 1, 2, 3, 4, 5, 2, 3, 4, 5, 6, 3, 4, 1, 2, 3, 4, 5, 2, 3, 4, 5, 6, 3, 4, 5, 2, 3, 4, 1, 2, 3, 4, 5, 2, 3, 4, 5, 2, 3, 4, 5, 2, 3, 4, 5, 6, 3, 4, 1, 2, 3, 4, 5, 2, 3, 4, 5, 6, 3, 4, 5, 2, 3, 4, 5, 6, 3, 4, 5, 2, 3, 4, 1, 2, 3, 4, 5, 2, 3, 4, 5, 6, 3, 4, 5, 2, 3, 4, 5
Offset: 1

Views

Author

Ilya Gutkovskiy, Oct 30 2020

Keywords

Links

Crossrefs

Cf. A001844, A002828, A101412, A234533, A338482.

A338479 Least number of hexagonal numbers needed to represent n.

Original entry on oeis.org

1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 6, 2, 3, 4, 1, 2, 3, 3, 4, 5, 2, 3, 4, 4, 5, 6, 3, 1, 2, 2, 3, 4, 4, 2, 3, 3, 4, 5, 5, 3, 4, 4, 2, 3, 1, 2, 3, 4, 3, 4, 2, 3, 4, 5, 4, 2, 3, 3, 4, 2, 3, 3, 4, 4, 5, 1, 2, 3, 4, 5, 3, 2, 2, 3, 3, 4, 4, 3, 3, 4, 2, 3, 4, 3, 4, 4, 3, 3, 4, 2, 1, 2, 3, 2, 3, 3, 2, 3, 4, 3, 3
Offset: 1

Views

Author

Ilya Gutkovskiy, Oct 29 2020

Keywords

Links

Crossrefs

Cf. A000384, A002828, A061336, A100878, A234533, A338480, A338481.

A338491 Least number of centered pentagonal numbers needed to represent n.

Original entry on oeis.org

1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 6, 2, 3, 4, 5, 1, 2, 3, 4, 5, 6, 2, 3, 4, 5, 6, 7, 3, 4, 5, 1, 2, 3, 4, 5, 6, 2, 3, 4, 5, 6, 7, 3, 4, 5, 6, 2, 3, 4, 5, 1, 2, 3, 4, 5, 6, 2, 3, 4, 5, 6, 2, 3, 4, 5, 6, 2, 3, 4, 5, 6, 7, 3, 4, 5, 1, 2, 3, 4, 5, 6, 2, 3, 4, 5, 6, 7, 3, 4, 5, 6, 2, 3, 4, 5, 6, 7, 3, 4, 5, 6
Offset: 1

Views

Author

Ilya Gutkovskiy, Oct 30 2020

Keywords

Links

Crossrefs

Cf. A005891, A100878, A101412, A234533, A338482, A338484, A338492, A338494.

A338492 Least number of centered heptagonal numbers needed to represent n.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 1, 2, 3, 4, 5, 6, 7, 8, 2, 3, 4, 5, 6, 7, 1, 2, 3, 4, 5, 6, 7, 8, 2, 3, 4, 5, 6, 7, 8, 9, 3, 4, 5, 6, 7, 1, 2, 3, 4, 5, 6, 7, 8, 2, 3, 4, 5, 6, 7, 8, 9, 3, 4, 5, 6, 7, 8, 2, 3, 4, 5, 6, 7, 1, 2, 3, 4, 5, 6, 7, 8, 2, 3, 4, 5, 6, 7, 8, 2, 3, 4, 5, 6, 7, 8, 2, 3, 4, 5, 6, 7, 8, 9, 3
Offset: 1

Views

Author

Ilya Gutkovskiy, Oct 30 2020

Keywords

Links

Crossrefs

Cf. A069099, A101412, A234533, A338480, A338482, A338484, A338491.
Showing 1-6 of 6 results.

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