OFFSET
0,5
COMMENTS
A008578 gives the noncomposite numbers, the prime numbers at the beginning of the 20th century which included 1.
a(2n) = 0, 0, 2, 4, 8, 12, 14, 20, 24, 24, ... always even?
a(2n+3) = 1, 3, 5, 9, 11, 17, 23, 23, 29, ... always odd?
First differences: 0, 0, 1, 1, 1, 1, 1, 3, 1, 3, -1, 3, 3, 3, 3, 1, -1, 1, 5, 7, ... .
EXAMPLE
a(3) = 1-0 = 1, a(4) = 2-0 = 2, a(5) = 3-0 = 3, a(6) = 5-1 = 4, a(6) = 7-2 = 5, ... .
MATHEMATICA
RecurrenceTable[{a[n + 3] == If[n == 0, 1, Prime[n]] - a[n], a[0] == 0, a[1] == 0, a[2] == 0}, a, {n, 0, 52}] (* Michael De Vlieger, Aug 08 2016 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul Curtz, Aug 08 2016
STATUS
approved