A168148 Row sums of triangle in A168030.

1, 1, 2, 2, 3, 4, 4, 3, 6, 6, 6, 4, 6, 7, 10, 6, 11, 12, 10, 6, 8, 8, 12, 8, 12, 11, 18, 12, 13, 16, 20, 11, 22, 22, 18, 12, 14, 14, 16, 10, 14, 12, 24, 16, 16, 18, 22, 12, 22, 23, 34, 20, 25, 28, 26, 17, 30, 26, 38, 24, 26, 31, 42, 22, 43, 44, 34, 22, 28, 26, 30, 20, 26

Offset

0,3

Links

G. C. Greubel, Table of n, a(n) for n = 0..5000

Formula

From G. C. Greubel, Jan 12 2023: (Start)

a(n) = Sum_{k=0..n} A168030(n, k).

a(n) = Sum_{k=0..n} (A118340(n, k) mod 2). (End)

Mathematica

t[n_, k_]:= t[n, k]= If[k<0 || k>n, 0, If[k==0, 1, If[n<=2*k, t[n, n-k -1] + t[n-1, k], t[n, n-k] + t[n-1, k]]]]; (* A118340 *)
Table[Sum[Mod[t[n, k], 2], {k, 0, n}], {n, 0, 80}] (* G. C. Greubel, Jan 12 2023 *)

Prog

(SageMath)
@CachedFunction
def t(n, k): # t = A118340
    if (k<0 or k>n): return 0
    elif (k==0): return 1
    elif (n>2*k): return t(n, n-k) + t(n-1, k)
    else: return t(n, n-k-1) + t(n-1, k)
def A168148(n): return sum( t(n, k)%2 for k in range(n+1))
[A168148(n) for n in range(81)] # G. C. Greubel, Jan 12 2023

Crossrefs

Cf. A118340, A168030.

Sequence in context: A334030 A285333 A086416 * A147968 A366320 A065167

Adjacent sequences: A168145 A168146 A168147 * A168149 A168150 A168151

Keyword

nonn

Author

Philippe Deléham, Nov 19 2009

Extensions

Terms a(16) onward added by G. C. Greubel, Jan 12 2023

Status

approved