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A103622 Smallest arithmetic mean of n distinct primes. 1
2, 4, 4, 7, 6, 11, 10, 13, 12, 17, 16, 21, 20, 24, 24, 29, 26, 32, 32, 36, 36, 41, 38, 45, 44, 49, 48, 53, 52, 58, 58, 63, 62, 68, 66, 72, 70, 77, 76, 83, 80, 87, 86, 92, 90, 97, 96, 102, 100, 108, 106, 113, 110, 118, 116, 123, 122, 129, 126, 133, 132, 139, 138, 145, 142 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Often a(2n+1) = a(2n) - 1. - Robert G. Wilson v, Jan 19 2007

LINKS

Table of n, a(n) for n=1..65.

EXAMPLE

a(1)=2 because (2)/1=2,

a(2)=4 because (3+5)/2=4,

a(3)=4 because (2+3+7)/3=4,

a(4)=7 because (3+5+7+13)/4=7,

a(5)=6 because (2+3+5+7+13)/5=6,

a(6)=11 because (3+5+7+11+17+23)/6=11,

a(7)=10 because (2+3+5+7+11+13+29)/7=10,

a(8)=13 because (3+5+7+11+13+17+19+29)/8=13,

a(9)=12 because (2+3+5+7+11+13+17+19+31)/9=12,

a(10)=17 because (3+5+7+11+13+17+19+23+29+43)/10=17, etc.

MATHEMATICA

f[n_] := Block[{k = 1, lst = Prime@ Range[ If[ OddQ@ n, 1, 2], n + 3]}, While[ Mod[Plus @@ Flatten@Subsets[lst, {n}, {k}], n] != 0, k++ ]; (Plus @@ Flatten@ Subsets[lst, {n}, {k}])/n]; Array[f, 65] (* Robert G. Wilson v, Jan 19 2007 *)

CROSSREFS

Cf. A072701.

Sequence in context: A082515 A062855 A274593 * A328853 A105774 A130805

Adjacent sequences:  A103619 A103620 A103621 * A103623 A103624 A103625

KEYWORD

easy,nonn

AUTHOR

Giovanni Teofilatto, Mar 25 2005

EXTENSIONS

Edited, corrected and extended by Robert G. Wilson v, Jan 19 2007

STATUS

approved

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Last modified December 6 20:22 EST 2021. Contains 349567 sequences. (Running on oeis4.)