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A101625
A bisection of the Stern-Jacobsthal numbers.
5
0, 1, 1, 5, 1, 21, 17, 69, 1, 277, 273, 1349, 257, 5141, 4113, 16453, 1, 65813, 65809, 329029, 65793, 1381397, 1118225, 4538437, 65537, 18088213, 17826065, 88081733, 16777473, 335549461, 268439569, 1073758277, 1, 4295033109, 4295033105
OFFSET
0,4
LINKS
FORMULA
a(n) = Sum_{k=0..n} (binomial(2n-k, k-1) mod 2)2^(k-1);
a(n) = A101624(2n+1).
a(0)=0, a(1)=1, a(n) = a(n-1) XOR (a(n-2)*4), where XOR is the bitwise exclusive-OR operator. - Alex Ratushnyak, May 06 2012
a(n+1) = Sum_{k=0..n} A106344(n,k)*4^(n-k). - Philippe Deléham, May 27 2012
PROG
(Python)
prpr = 0
prev = 1
for i in range(99):
current = (prev)^(prpr*4)
print(prpr, end=', ')
prpr = prev
prev = current
# Alex Ratushnyak, May 06 2012
CROSSREFS
Cf. A002450.
Sequence in context: A095368 A029757 A146056 * A051929 A347487 A213118
KEYWORD
easy,nonn
AUTHOR
Paul Barry, Dec 10 2004
STATUS
approved