|
|
A280029
|
|
a(1)=3; thereafter, if n odd, a(n) = a(n-1)-st prime, and if n even, a(n) = a(n-1)-st nonprime.
|
|
3
|
|
|
3, 6, 13, 21, 73, 98, 521, 636, 4721, 5439, 53323, 59318, 737183, 801235, 12215237, 13068626, 238205651, 251987681, 5381022817, 5644769560, 138933578143, 144807081479, 4053430178401, 4203399920996, 132332669898119, 136669373292795, 4793783797371011
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
This is the sequence S_2 mentioned in A141436. The primes and nonprimes alternate.
|
|
LINKS
|
|
|
MAPLE
|
|
|
MATHEMATICA
|
nonPrime[n_Integer] := FixedPoint[n + PrimePi@# &, n + PrimePi@ n]; a[n_] := a[n] = If[OddQ@ n, Prime@ a[n -1], nonPrime[ a[n -1]]]; a[1] = 3; Array[a, 26] *( Robert G. Wilson v, Dec 28 2016 *)
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
EXTENSIONS
|
|
|
STATUS
|
approved
|
|
|
|