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A128233
Average of p(n) and p(p(n)), where p(k) is the k-th prime.
1
4, 8, 12, 21, 27, 38, 43, 53, 69, 79, 97, 110, 117, 129, 147, 168, 172, 199, 212, 220, 240, 257, 275, 303, 324, 333, 347, 354, 365, 418, 435, 455, 468, 504, 514, 538, 565, 579, 602, 621, 634, 672, 682, 699, 708, 754, 816, 830, 838, 852, 869, 882, 924, 939, 966
OFFSET
2,1
EXAMPLE
a(4)=12 because p(4)=7 and p(7)=17.
MAPLE
a:=n->(ithprime(n)+ithprime(ithprime(n)))/2: seq(a(n), n=2..70);
MATHEMATICA
Table[Mean[{Prime[n], Prime[Prime[n]]}], {n, 2, 60}] (* Harvey P. Dale, Jul 30 2020 *)
CROSSREFS
Cf. A128234.
Sequence in context: A311664 A190891 A188293 * A092108 A015781 A130643
KEYWORD
nonn
AUTHOR
Emeric Deutsch, Feb 20 2007
STATUS
approved