A026999 Distinct values of A026998.

1, 4, 8, 11, 13, 19, 26, 29, 34, 43, 53, 54, 64, 73, 76, 89, 101, 103, 118, 134, 151, 169, 171, 174, 188, 196, 199, 208, 229, 251, 274, 281, 298, 323, 349, 370, 376, 404, 431, 433, 463, 487, 494, 518, 521, 526, 559, 593, 628, 634, 664, 701, 739, 743, 778, 818, 859, 901, 944, 988, 1033, 1079, 1126, 1148

Offset

1,2

Links

G. C. Greubel, Table of n, a(n) for n = 1..2500 (286..2500 corrected by Sean A. Irvine)

Mathematica

m:=300;
A027960[n_, k_]:= A027960[n, k]= If[k>2*n, 0, If[k<n+1, LucasL[k+1], A027960[n-1, k-1] + A027960[n-1, k-2]]];
A026998[n_, k_]:= A026998[n, k]= A027960[n, 2*k];
A026999= Table[A027960[n, 2*k], {n, 0, Floor[5*m/4]}, {k, 0, n}]//Flatten//Union;
Table[A026999[[n]], {n, m}] (* G. C. Greubel, Aug 21 2025; Mar 01 2026 *)

Prog

(SageMath)
m=300
@CachedFunction
def t(n, k): # t = A027960
    if (k>2*n): return 0
    elif (k<n+1): return lucas_number2(k+1, 1, -1)
    else: return t(n-1, k-2) + t(n-1, k-1)
def A026998(n, k): return t(n, 2*k)
A026998_list= flatten([[A026998(n, k) for k in range(n+1)] for n in range((5*m//4)+1)])
A026999= sorted(Set( A026998_list ))
print([A026999[n] for n in range(m)]) # G. C. Greubel, Aug 21 2025

Crossrefs

Cf. A026998, A027960.

Sequence in context: A287242 A311028 A311029 * A133291 A356105 A311030

Adjacent sequences: A026996 A026997 A026998 * A027000 A027001 A027002

Keyword

nonn

Author

Clark Kimberling

Extensions

More terms added by G. C. Greubel, Aug 21 2025

Status

approved