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A191980 Ordered sums f+5g, where f and g are Lucas numbers (A000032 beginning at 1). 4
6, 8, 9, 12, 16, 18, 19, 21, 22, 23, 24, 26, 27, 31, 33, 34, 36, 38, 39, 42, 44, 46, 49, 52, 53, 56, 58, 59, 62, 64, 66, 67, 73, 81, 82, 84, 91, 93, 94, 96, 97, 101, 102, 108, 111, 119, 128, 131, 137, 138, 143, 146, 148, 149, 152, 156, 158, 163, 166, 174 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..60.

MATHEMATICA

c = 1; d = 5; f[n_] := LucasL[n];

g[n_] := c*f[n]; h[n_] := d*f[n];

t[i_, j_] := h[i] + g[j];

u = Table[t[i, j], {i, 1, 20}, {j, 1, 20}];

v = Union[Flatten[u]]    (* A191980 *)

t1[i_, j_] := If[g[i] - h[j] > 0, g[i] - h[j], 0]

u1 = Table[t1[i, j], {i, 1, 20}, {j, 1, 20}];

v1 = Union[Flatten[u1]]  (*A 191981: c*f(i)-d*f(j) *)

g1[n_] := d*f[n]; h1[n_] := c*f[n];

t2[i_, j_] := If[g1[i] - h1[j] > 0, g1[i] - h1[j], 0]

u2 = Table[t2[i, j], {i, 1, 20}, {j, 1, 20}];

v2 = Union[Flatten[u2]]  (* A191982: d*f(i)-c*f(j) *)

v3 = Union[v1, v2]       (* A191983 *)

With[{nn=20}, Select[Union[(#[[1]]+5#[[2]]&/@Tuples[LucasL[Range[nn]], 2])], #<=LucasL[nn]+5&]] (* Harvey P. Dale, Dec 07 2018 *)

CROSSREFS

Cf. A191981, A191981, A191982, A191983.

Sequence in context: A337381 A305704 A043720 * A304412 A161982 A285275

Adjacent sequences:  A191977 A191978 A191979 * A191981 A191982 A191983

KEYWORD

nonn

AUTHOR

Clark Kimberling, Jun 20 2011

STATUS

approved

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Last modified February 25 12:28 EST 2021. Contains 341606 sequences. (Running on oeis4.)