OFFSET
0,6
COMMENTS
A143792(n) <= a(n) for n > 0. - Reinhard Zumkeller, Sep 08 2008
For n > 1: number of primes in n-th row of A165416, lengths in n-th row of A225243. - Reinhard Zumkeller, Jul 17 2015, Aug 14 2013
LINKS
Reinhard Zumkeller, Table of n, a(n) for n = 0..10000
EXAMPLE
n=7 -> '111' contains 2 different binary substrings which are primes: '11' (11b or b11) and '111' itself, therefore a(7)=2.
MATHEMATICA
a[n_] := (bits = IntegerDigits[n, 2]; lg = Length[bits]; Reap[Do[If[PrimeQ[p = FromDigits[bits[[i ;; j]], 2]], Sow[p]], {i, 1, lg-1}, {j, i+1, lg}]][[2, 1]] // Union // Length); a[0] = a[1] = 0; Table[a[n], {n, 0, 104}] (* Jean-François Alcover, May 23 2013 *)
PROG
(Haskell)
a078826 n | n <= 1 = 0
| otherwise = length $ a225243_row n
-- Reinhard Zumkeller, Aug 14 2013
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Reinhard Zumkeller, Dec 08 2002
STATUS
approved