A092929 -id:A092929 - cp's OEIS frontend

A164931 n times the n-th noncomposite.

1, 4, 9, 20, 35, 66, 91, 136, 171, 230, 319, 372, 481, 574, 645, 752, 901, 1062, 1159, 1340, 1491, 1606, 1817, 1992, 2225, 2522, 2727, 2884, 3103, 3270, 3503, 4064, 4323, 4658, 4865, 5364, 5587, 5966, 6357, 6680, 7093, 7518, 7783, 8404, 8685, 9062, 9353

Offset: 1

Jaroslav Krizek, Aug 31 2009

Does some n > 2 exist such that n * prime(n-1) / (n + prime(n-1)), i.e. a(n) / A090178(n) is an integer?
Complement of A171519. - Jaroslav Krizek, Dec 13 2009
Partial sums of A092929. - Gionata Neri, May 26 2015

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

Module[{nn=200,cmps},cmps=Select[Range[nn],!CompositeQ[#]&];Times@@@ Thread[ {cmps,Range[Length[cmps]]}]] (* Harvey P. Dale, Jul 25 2021 *)

a(n)=if(n>1,n*prime(n-1),1) \\ Charles R Greathouse IV, Jun 02 2015

a(n) = n*A008578(n).

Correction for change of offset in A008578 by Jaroslav Krizek, Jan 27 2010

A092930 n-th partial arithmetic mean is equal to the n-th composite number.

Original entry on oeis.org

4, 8, 12, 12, 14, 22, 26, 22, 24, 36, 40, 32, 34, 50, 39, 41, 43, 45, 66, 70, 53, 55, 57, 59, 86, 64, 66, 96, 100, 74, 76, 110, 81, 83, 85, 87, 126, 92, 94, 96, 98, 142, 146, 106, 108, 110, 112, 162, 117, 119, 172, 176, 127, 129, 131, 133, 192, 138, 140, 202, 145, 147

Offset: 1

Amarnath Murthy, Mar 19 2004

Cf. A092929.

More terms from Ray Chandler, Mar 23 2004

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A164931 n times the n-th noncomposite.

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A092930 n-th partial arithmetic mean is equal to the n-th composite number.

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