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A335040
Numbers whose binary representation encodes a (binary) max-heap on elements from the set {0,1} with root at the most significant bit.
4
0, 1, 2, 3, 4, 5, 6, 7, 8, 10, 12, 13, 14, 15, 16, 20, 24, 25, 26, 27, 28, 29, 30, 31, 32, 40, 41, 48, 50, 52, 54, 56, 57, 58, 59, 60, 61, 62, 63, 64, 80, 81, 82, 83, 96, 100, 104, 108, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126
OFFSET
1,3
LINKS
Eric Weisstein's World of Mathematics, Heap
Wikipedia, Binary heap
MAPLE
q:= proc(n) local i, l; l:= convert(n, base, 2);
for i from 2 to nops(l) do
if l[-i]>l[-iquo(i, 2)] then return false fi
od; true
end:
a:= proc(n) option remember; local k: for k from 1+
`if`(n=1, -1, a(n-1)) while not q(k) do od; k
end:
seq(a(n), n=1..70);
CROSSREFS
Cf. A000225 (subsequence), A335039, A335041, A335042 (subsequence).
Sequence in context: A039273 A039164 A263977 * A270427 A270189 A257672
KEYWORD
nonn,base
AUTHOR
Alois P. Heinz, May 20 2020
STATUS
approved