A165239 Integers of the form "partial sum of the first k nonprimes divided by the k-th nonprime."

1, 8, 9, 46, 172, 1188, 4708, 28611, 480644, 785709

Offset

1,2

Comments

Integers of the form A051349(k)/A018252(k), generated by k= 1, 14, 16, 88, 334, 2345, 9328,... - R. J. Mathar, Oct 29 2011

Links

Table of n, a(n) for n=1..10.

Example

(1 + 4 + 6 + 8 + 9 + 10 + 12 + 14 + 15 + 16 + 18 + 20 + 21 + 22)/22=8,
(1 + 4 + 6 + 8 + 9 + 10 + 12 + 14 + 15 + 16 + 18 + 20 + 21 + 22 + 24 + 25)/25=9
(1 + 4 + 6 + 8 + 9 + 10 + 12 + 14 + 15 + 16 + 18 + 20 + 21 + 22 + 24 + 25 + 26 + 27 + 28 + 30 + 32 + 33 + 34 + 35 + 36 + 38 + 39 + 40 + 42 + 44 + 45 + 46 + 48 + 49 + 50 + 51 + 52 + 54 + 55 + 56 + 57 + 58 + 60 + 62 + 63 + 64 + 65 + 66 + 68 + 69 + 70 + 72 + 74 + 75 + 76 + 77 + 78 + 80 + 81 + 82 + 84 + 85 + 86 + 87 + 88 + 90 + 91 + 92 + 93 + 94 + 95 + 96 + 98 + 99 + 100 + 102 + 104 + 105 + 106 + 108 + 110 + 111 + 112 + 114 + 115 + 116 + 117 + 118)/118=46

Mathematica

lst={}; a=0; Do[If[ !PrimeQ[n], m=n; a+=m; If[IntegerQ[a/n]&&a!=n, AppendTo[lst, a/n]]], {n, 5*9!}]; lst

Crossrefs

Cf. A160758

Sequence in context: A041138 A048068 A037957 * A103315 A175931 A270013

Adjacent sequences: A165236 A165237 A165238 * A165240 A165241 A165242

Keyword

nonn

Author

Vladimir Joseph Stephan Orlovsky, Sep 09 2009

Status

approved