A344636
Numbers k such that half the numbers from 0 to k inclusive contain the digit "1".
Original entry on oeis.org
1, 17, 23, 161, 269, 271, 1457, 3397, 3419, 3421, 13121, 44685, 118097, 674909, 674933, 1062881
Offset: 1
1 is a term since among the numbers 0,1 exactly half contain a digit "1".
17 is a term since among the numbers 0,1,2,...,17 exactly half contain a digit "1".
- Andrew Hilton, 101 Puzzles to Solve on your Microcomputer, 1984, HARRAP, page 57.
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Select[2Range@2000,Length@Select[Range[0,#-1],MemberQ[IntegerDigits@#,1]&]==#/2&]-1 (* Giorgos Kalogeropoulos, Jul 28 2021 *)
A344474
Least number k such that half of the numbers from 0 to k inclusive contain the digit n.
Original entry on oeis.org
1, 1, 2915, 39365, 472391, 590489, 6377291, 7440173, 8503055, 9565937
Offset: 0
a(0)=1 since among the numbers 0,1 exactly half contain a digit "0" and 1 is the smallest number where this occurs.
a(1)=1 since among the numbers 0,1 exactly half contain a digit "1" and 1 is the smallest number where this occurs.
a(2)=2915 since among the numbers 0,1,2,...,2915 exactly half contain a digit "2" and 2915 is the smallest number where this occurs.
a(3)=39365 since among the numbers 0,1,2,...,39365 exactly half contain a digit "3" and 39365 is the smallest number where this occurs.
- Andrew Hilton, 101 Puzzles to Solve on your Microcomputer, 1984, HARRAP, page 57.
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a(n)={if(n>=1&&n<10, my(k=0); while(n*(2*9^k-10^k)>10^k, k++); 2*9^k*n - 1, n==0)} \\ Andrew Howroyd, May 25 2021
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for z in range (0, 10):
z_s = str(z)
counts=0
for x in range (0,1000000000):
x_s = str(x)
if z_s in x_s:
counts += 1
if counts / (x+1) == 0.5:
print(x)
break
Showing 1-2 of 2 results.
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