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A247987 Numbers k such that A247985(k+1) - A247985(k) = 3. 3
1, 3, 4, 6, 7, 8, 10, 11, 12, 14, 15, 17, 18, 19, 21, 22, 24, 25, 26, 28, 29, 31, 32, 33, 35, 36, 38, 39, 40, 42, 43, 45, 46, 47, 49, 50, 51, 53, 54, 56, 57, 58, 60, 61, 63, 64, 65, 67, 68, 70, 71, 72, 74, 75, 77, 78, 79, 81, 82, 83, 85, 86, 88, 89, 90, 92 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Complement of A247986.

LINKS

Clark Kimberling, Table of n, a(n) for n = 1..1000

MATHEMATICA

z = 100; p[k_] := p[k] = Product[(k^2 + h)/(k^2 - h), {h, 1, k}] (* Finch p. 14 *)

N[Table[p[n] - E, {n, 2, z}]]

f[n_] := f[n] = Select[1 + Range[z], p[#] - E < 1/n &, 1];

u = Flatten[Table[f[n], {n, 1, z}]] ;  (* A247985 *)

v = Differences[u];

Flatten[Position[v, 2]]; (* A247986 *)

Flatten[Position[v, 3]]; (* A247987 *)

CROSSREFS

Cf. A247985, A247986.

Sequence in context: A275481 A234349 A042954 * A062975 A276218 A047299

Adjacent sequences:  A247984 A247985 A247986 * A247988 A247989 A247990

KEYWORD

nonn,easy

AUTHOR

Clark Kimberling, Sep 29 2014

STATUS

approved

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Last modified April 13 03:43 EDT 2021. Contains 342934 sequences. (Running on oeis4.)