OFFSET
1,1
COMMENTS
2 together with average of odd primes taken two at a time without overlaps, i.e., 2 together with average of (3,5), (7,11), (13,17), etc. - Harvey P. Dale, Apr 09 2018
LINKS
Harry J. Smith, Table of n, a(n) for n = 1..20000
Donald Mills, Some Interesting Sequences.
FORMULA
a(1)=2, a(n) = (p(2n-2) + p(2n-1))/2 for n>1, where p(i) is the i-th prime.
MAPLE
with(linalg): v := linalg[vector](100): v[1] := 2: for j from 2 to 100 do v[j] := (ithprime(2*j-2)+ithprime(2*j-1))/2: od: print(v);
MATHEMATICA
Join[{2}, Mean/@Partition[Prime[Range[2, 121]], 2]] (* Harvey P. Dale, Apr 09 2018 *)
PROG
(PARI) { write("b058296.txt", 1, " ", 2); p2=2; for (n=2, 20000, p1=nextprime(p2+1); p2=nextprime(p1+1); a=(p1+p2)/2; write("b058296.txt", n, " ", a); ); } \\ Harry J. Smith, May 30 2009
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Donald Mills (dmills(AT)math.siu.edu), Feb 16 2003
STATUS
approved