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A143015
a(1) = 1. a(n) = the smallest integer >=2 such that (product{k=1 to n} a(k)) in binary is a palindrome.
2
1, 3, 3, 3, 7, 13, 5, 13, 57, 223, 5419, 17, 241, 4192257, 16773121, 17, 241
OFFSET
1,2
COMMENTS
All terms are odd.
There are an infinite number of terms.
a(18) > 11000000001. - Robert G. Wilson v, Jun 30 2009
FORMULA
For n>=2, a(n) = A143014(n)/A143014(n-1).
MATHEMATICA
f[n_] := f[n] = Block[{k = 3, a = Times @@ Table[ f@i, {i, n - 1}]}, While[ id = IntegerDigits[a*k, 2]; id != Reverse@id, k += 2]; k]; f[1]=1; Array[f, 17] (* Robert G. Wilson v, Jun 30 2009 *)
CROSSREFS
Sequence in context: A342335 A137438 A098524 * A295671 A107709 A111521
KEYWORD
base,more,nonn
AUTHOR
Leroy Quet, Jul 15 2008
EXTENSIONS
a(6)-a(17) from Ray Chandler, Jun 21 2009
STATUS
approved