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A190250 Positions of 1 in A190248. 5
1, 4, 6, 7, 9, 12, 14, 15, 17, 19, 20, 22, 25, 27, 28, 30, 33, 35, 38, 40, 41, 43, 46, 48, 49, 51, 54, 56, 59, 61, 62, 64, 67, 69, 70, 72, 74, 75, 77, 80, 82, 83, 85, 88, 90, 93, 95, 96, 98, 101, 103, 104, 106, 108, 109, 111, 114, 116, 117, 119, 122, 124, 125, 127, 129, 130, 132, 135, 137, 138, 140, 143, 145, 148, 150, 151, 153, 156, 158, 159, 161 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Numbers n such that 1/4 < {n*phi} < 3/4, where phi is the golden ratio (1+sqrt(5))/2 and { } denotes fractional part. - Burghard Herrmann, Nov 14 2017

LINKS

G. C. Greubel, Table of n, a(n) for n = 1..5500

Burghard Herrmann, Characterization of some golden ratio sequences

MATHEMATICA

u = GoldenRatio; v = u^2; w=u^3;

f[n_] := Floor[n*u + n*v + n*w] - Floor[n*u] - Floor[n*v] - Floor[n*w]

t = Table[f[n], {n, 1, 120}] (*A190248*)

Flatten[Position[t, 0]]      (*A190249*)

Flatten[Position[t, 1]]      (*A190250*)

Flatten[Position[t, 2]]      (*A190251*)

PROG

(PARI) isok(n) = my(u=(1+sqrt(5))/2); floor(2*n+4*n*u)-floor(n*u)-floor(n+n*u)-floor(n+2*n*u) == 1; \\ Michel Marcus, Nov 14 2017

CROSSREFS

Cf. A190248, A190249, A190251.

Sequence in context: A256792 A085817 A177688 * A047508 A089960 A067888

Adjacent sequences:  A190247 A190248 A190249 * A190251 A190252 A190253

KEYWORD

nonn

AUTHOR

Clark Kimberling, May 06 2011

STATUS

approved

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Last modified October 16 16:08 EDT 2019. Contains 328101 sequences. (Running on oeis4.)