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A081518 Final term in row n of A081520. 3
1, 2, 6, 6, 20, 8, 42, 14, 24, 15, 110, 16, 156, 22, 30, 30, 272, 26, 342, 32, 48, 38, 506, 34, 120, 46, 78, 48, 812, 39, 930, 62, 81, 62, 110, 52, 1332, 70, 99, 65, 1640, 57, 1806, 78, 95, 86, 2162, 70, 336, 82, 135, 94, 2756, 80, 198, 96, 152, 110, 3422, 81, 3660, 118 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

a(p) = p(p-1) if p is a prime.

a(p^k) = p (p^k - 1) if p is a prime and k >= 1. - Robert Israel, May 21 2015

LINKS

Ivan Neretin, Table of n, a(n) for n = 1..1000

MAPLE

A:= n -> select(t->igcd(t, n)>1, [$1..n^2])[n-1]:

1, seq(A(n), n=2..100); # Robert Israel, May 21 2015

MATHEMATICA

Table[Join[{1}, Select[Range[n^2], GCD[n, #] > 1 &, n - 1]][[-1]], {n, 1, 60}](* Ivan Neretin, May 21 2015 *)

CROSSREFS

Cf. A081519, A081520.

Sequence in context: A111410 A240087 A083774 * A258702 A320916 A119551

Adjacent sequences:  A081515 A081516 A081517 * A081519 A081520 A081521

KEYWORD

nonn

AUTHOR

Amarnath Murthy, Mar 27 2003

EXTENSIONS

More terms from Ryan Propper, Nov 05 2005

STATUS

approved

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Last modified June 6 11:02 EDT 2020. Contains 334836 sequences. (Running on oeis4.)