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A077216
Smallest prime(k) such that 2^n divides the product of composite numbers between prime(k) and prime(k+1) but 2^(n+1) does not.
0
2, 5, 3, 19, 7, 13, 23, 47, 31, 89, 139, 113, 199, 293, 631, 317, 1069, 509, 2503, 1129, 1759, 2039, 887, 1951, 4027, 3967, 2477, 2971, 3271, 6917, 4831, 5591, 10799, 5119, 14107, 9973, 1327, 39461, 16381, 20809, 11743, 15683, 61169, 52391, 33247, 45439
OFFSET
0,1
EXAMPLE
a(0) = 2, a(1) = 5, a(2) = 3 a(5) = 13 as 2^5 = 32 divides 14*15*16 but 2^6=64 does not.
MATHEMATICA
f[n_] := Block[{k = 1}, While[ Mod[Times @@ Select[ Range[Prime@k, Prime[k + 1]], ! PrimeQ@# &], 2^n] != 0 || Mod[Times @@ Select[ Range[Prime@k, Prime[k + 1]], ! PrimeQ@# &], 2^(n + 1)] == 0, k++ ]; Prime@k]; Table[ f[n], {n, 0, 45}] (* Robert G. Wilson v, Apr 06 2006 *)
CROSSREFS
Sequence in context: A248576 A087228 A285743 * A227617 A309080 A058357
KEYWORD
nonn
AUTHOR
Amarnath Murthy, Nov 02 2002
EXTENSIONS
More terms from Robert G. Wilson v, Apr 06 2006
STATUS
approved