A030350 a(n) = (# 1's)-(# 2's) in first n terms of A030341.

0, 1, 0, 0, 1, 2, 3, 2, 3, 3, 2, 3, 2, 1, 0, 0, 0, 1, 2, 2, 3, 2, 2, 3, 3, 4, 5, 6, 7, 8, 7, 8, 9, 9, 8, 9, 10, 9, 10, 9, 8, 9, 9, 9, 8, 9, 9, 8, 7, 7, 6, 6, 7, 6, 7, 8, 7, 6, 7, 6, 6, 5, 4, 5, 4, 3, 2, 1, 0, 0, 0, 0, 1, 2, 2, 2, 3, 2, 2, 2, 3, 3, 4, 4, 5, 6, 7, 7, 8, 7

Offset

1,6

Comments

For k >= 1, a(3^k * (k - 1/2) + 1/2) = 1 and a(3^k * (k - 1/2) + 3/2) = a(3^k * (k - 1/2) + 5/2) = 0. - Robert Israel, Jun 23 2024

Links

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

Maple

R:= 0: t:= 0:
for i from 1 to 100 do
  L:= convert(i, base, 3);
  for j from 1 to nops(L) do
    if L[j] = 1 then t:= t+1 elif L[j] = 2 then t:= t-1 fi;
    R:= R, t;
  od
od:
R; # Robert Israel, Jun 23 2024

Crossrefs

Cf. A030341.

Sequence in context: A200323 A075370 A332297 * A026240 A124474 A282162

Adjacent sequences: A030347 A030348 A030349 * A030351 A030352 A030353

Keyword

nonn,look

Author

Clark Kimberling

Extensions

a(1) = 0 inserted by Robert Israel, Jun 23 2024

Status

approved