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Numbers whose decimal expansion is a concatenation of 3 consecutive increasing numbers.
Duplicate of A001703.
1,0,1
a(n) = (n-1)*10^floor[log10(b)+1]+b, with b=n*10^floor[log10(n+1)+1]+n+1 and n>=1. - Paolo P. Lava, Aug 04 2008
P:=proc(i) local a, b, c, n; for n from 1 by 1 to i do b:=n*10^evalf(floor(log10(n+1)+1))+n+1; a:=floor((n-1)*10^evalf(floor(log10(b)+1))+b); print(a); od; end: P(1000); # Paolo P. Lava, Aug 04 2008
# second Maple program:
a:= n-> parse(cat(n-1, n, n+1)):
seq(a(n), n=1..50); # Alois P. Heinz, Mar 29 2017
nonn,base,changed
dead
Artur Jasinski, Jan 14 2007
Missing 192021 inserted. - R. J. Mathar, Mar 29 2017
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P:=proc(i) local a, b, c, n; for n from 1 by 1 to i do b:=n*10^evalf(floor(log10(n+1)+1))+n+1; a:=floor((n-1)*10^evalf(floor(log10(b)+1))+b); print(a); od; end: P(1000); # Paolo P. Lava, Aug 04 2008]
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a(n) = (n-1)*10^floor[log10(b)+1]+b, with b=n*10^floor[log10(n+1)+1]+n+1 and n>=1 [From _. - _Paolo P. Lava_, Aug 04 2008]
(Maple) P:=proc(i) local a, b, c, n; for n from 1 by 1 to i do b:=n*10^evalf(floor(log10(n+1)+1))+n+1; a:=floor((n-1)*10^evalf(floor(log10(b)+1))+b); print(a); od; end: P(1000); [From _# _Paolo P. Lava_, Aug 04 2008]
# second Maple program:
a:= n-> parse(cat(n-1, n, n+1)):
seq(a(n), n=1..50); # Alois P. Heinz, Mar 29 2017
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12, 123, 234, 345, 456, 567, 678, 789, 8910, 91011, 101112, 111213, 121314, 131415, 141516, 151617, 161718, 171819, 181920, 192021, 202122, 212223, 222324, 232425, 242526, 252627, 262728, 272829, 282930, 293031, 303132, 313233, 323334, 333435, 343536, 353637, 363738, 373839, 383940, 394041
Missing 192021 inserted. - R. J. Mathar, Mar 29 2017
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12, 123, 234, 345, 456, 567, 678, 789, 8910, 91011, 101112, 111213, 121314, 131415, 141516, 151617, 161718, 171819, 181920, 192021, 202122, 212223, 222324, 232425, 242526, 252627, 262728, 272829, 282930, 293031, 303132, 313233, 323334, 333435, 343536, 353637, 363738, 373839, 383940, 394041
Missing 192021 inserted. - R. J. Mathar, Mar 29 2017
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