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A131981
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Number of early bird numbers <= n.
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4
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 4, 5, 5, 6, 6, 6, 6, 6, 6, 6, 7, 8, 9, 9, 10, 10, 10, 10, 10, 10, 11, 12, 13, 14, 14, 15, 15, 15, 15, 15, 16, 17, 18, 19, 20, 20, 21, 21, 21, 21, 22, 23, 24, 25, 26, 27, 27, 28, 28, 28, 29, 30, 31, 32
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listen;
history;
text;
internal format)
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OFFSET
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1,21
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COMMENTS
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a(n) = number of k such that A116700(k) <= n; a(n) = n - number of k such that A131881(k) <= n.
A131982 gives numbers n such that a(n) = n/2, or numbers n such that (number of k such that A116700(k) <= n) = (number of k such that A131881(k) <= n).
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LINKS
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EXAMPLE
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There are two early bird numbers <= 21, viz. 12 and 21, hence a(21) = 2.
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PROG
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(JBASIC)
s$ = "" : d = 0
FOR n = 1 TO 84
sn$ = str$(n)
IF instr(s$, sn$) > 0 THEN d = d+1
s$ = s$ + sn$ : print d ; ", ";
NEXT
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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STATUS
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approved
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