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A335426
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a(1) = 0; thereafter a(2^(2^k)) = 0 for k > 0, and for other even numbers n, a(n) = 1+a(n/2), and for odd numbers n, a(n) = 2*a(A064989(n)).
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2
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0, 1, 2, 0, 4, 3, 8, 1, 0, 5, 16, 4, 32, 9, 6, 0, 64, 1, 128, 6, 10, 17, 256, 5, 0, 33, 2, 10, 512, 7, 1024, 1, 18, 65, 12, 2, 2048, 129, 34, 7, 4096, 11, 8192, 18, 8, 257, 16384, 6, 0, 1, 66, 34, 32768, 3, 20, 11, 130, 513, 65536, 8, 131072, 1025, 12, 2, 36, 19, 262144, 66, 258, 13, 524288, 3, 1048576, 2049, 2, 130, 24, 35, 2097152, 8, 0, 4097
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OFFSET
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1,3
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LINKS
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FORMULA
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a(1) = 0, and then after, a(2^(2^k)) = 0 for k > 0, and for other even numbers n, a(n) = 1+a(n/2), and for odd numbers n, a(n) = 2*a(A064989(n)).
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PROG
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(PARI)
A064989(n) = {my(f); f = factor(n); if((n>1 && f[1, 1]==2), f[1, 2] = 0); for (i=1, #f~, f[i, 1] = precprime(f[i, 1]-1)); factorback(f)};
A209229(n) = (n && !bitand(n, n-1));
\\ Alternatively:
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CROSSREFS
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Cf. A082522 (gives indices of zeros after a(1)=0).
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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