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Rémy Sigrist, <a href="/A333441/b333441.txt">Table of n, a(n) for n = 1..8789</a> (terms < 2^16)
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The first terms, alongside their binary representation with a possible pairing, are:
n a(n) bin(a(n))
-- ---- ------------
1 0 0
2 3 (11)
3 9 (1(00)1)
4 12 (11)(00)
5 15 (11)(11)
6 33 (1(00)(00)1)
7 36 (1(00)1)(00)
8 39 (1(00)1)(11)
9 45 (1(0(11)0)1)
10 48 (11)(00)(00)
11 51 (11)(00)(11)
12 54 (11)(0(11)0)
13 57 (11)(1(00)1)
14 60 (11)(11)(00)
15 63 (11)(11)(11)
allocated for Rémy Sigrist
Numbers where each binary digit can be paired with a digit of the same value at another position so that two pairs can be nested but cannot otherwise overlap.
0, 3, 9, 12, 15, 33, 36, 39, 45, 48, 51, 54, 57, 60, 63, 129, 132, 135, 141, 144, 147, 150, 153, 156, 159, 165, 177, 180, 183, 189, 192, 195, 198, 201, 204, 207, 210, 216, 219, 222, 225, 228, 231, 237, 240, 243, 246, 249, 252, 255, 513, 516, 519, 525, 528, 531
1,2
This sequence is a binary variant of A333440.
(PARI) is(n, base=2) = { my (u=0, s=0); while (n, my (d=n%base); if (u && s%base==d, u--; s\=base, u++; s=s*base+d); n\=base); u==0 }
Cf. A333440.
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nonn,base
Rémy Sigrist, Mar 21 2020
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