A025011 - OEIS

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A025011

a(1) = 7; a(n+1) = a(n)-th composite.

7, 14, 24, 36, 52, 74, 100, 133, 174, 222, 284, 356, 442, 543, 665, 805, 969, 1161, 1383, 1643, 1939, 2278, 2665, 3108, 3614, 4189, 4840, 5577, 6412, 7348, 8400, 9584, 10912, 12392, 14049, 15903, 17963, 20253, 22801, 25624, 28757, 32214, 36044, 40273, 44943

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

LINKS

Chai Wah Wu, Table of n, a(n) for n = 1..901

MATHEMATICA

g[ n_Integer ] := (k = n + PrimePi[ n ] + 1; While[ k - PrimePi[ k ] - 1, k++ ]; k); NestList[ g, 7, 45 ]

With[{cmps=Select[Range[100000], CompositeQ]}, NestList[cmps[[#]]&, 7, 50]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Jul 08 2017 *)

CROSSREFS

Cf. A006508, A025010.

Sequence in context: A297663 A190779 A188383 * A169874 A340797 A340796

Adjacent sequences: A025008 A025009 A025010 * A025012 A025013 A025014

KEYWORD

nonn

AUTHOR

David W. Wilson

STATUS

approved