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

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

1,2

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Eric Weisstein's World of Mathematics, Hexagonal Pyramidal Number

Index to sequences related to pyramidal numbers

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

Crossrefs

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

Sequence in context: A010885 A338480 A234533 * A053828 A033927 A104414

Adjacent sequences: A338492 A338493 A338494 * A338496 A338497 A338498

Keyword

nonn

Author

Ilya Gutkovskiy, Oct 30 2020

Status

approved