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A264387 2*(1+2*a(n)) is the n-th even squarefree number A039956(n), n >= 1. 3
0, 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 14, 15, 16, 17, 18, 19, 20, 21, 23, 25, 26, 27, 28, 29, 30, 32, 33, 34, 35, 36, 38, 39, 41, 42, 43, 44, 45, 46, 47, 48, 50, 51, 52, 53, 54, 55, 56, 57, 59, 61, 63, 64, 65, 66, 68, 69, 70, 71, 72, 74, 75, 77, 78, 79, 80, 81, 82, 83, 86, 88, 89, 90, 91, 92, 93, 95, 96, 97, 98, 99, 100 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

G. C. Greubel, Table of n, a(n) for n = 1..10000

FORMULA

a(n) = (A039956(n) - 2)/4, n >= 1.

MATHEMATICA

(# - 2)/4 & /@ Select[2 Range@ 202, SquareFreeQ] (* Michael De Vlieger, Dec 23 2015 *)

CROSSREFS

Cf. A039956.

Sequence in context: A090240 A137407 A261406 * A282843 A074137 A206027

Adjacent sequences:  A264384 A264385 A264386 * A264388 A264389 A264390

KEYWORD

nonn,easy

AUTHOR

Wolfdieter Lang, Dec 23 2015

STATUS

approved

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Last modified August 25 16:14 EDT 2019. Contains 326324 sequences. (Running on oeis4.)