30000000

Appears in sequences

• Powers of 3 written in base 9.at n=15A004663
• Powers of 3 written in base 27.at n=22A004669
• Numbers k such that k^2 contains exactly 2 distinct digits.at n=41A016069
• a(n)/10000000 gives sqrt(n) to 7 places.at n=8A027664
• a(n) is root of square starting with digit 9: first term of runs.at n=12A035076
• Useless numbers: numbers written in English without any of the letters e, s or u.at n=15A073418
• Expansion of (1-7x)/(1-10x).at n=8A093138
• a(1) = 1; for n>1, a(n) = smallest number > a(n-1) such that last digit of a(n-1) + first digit of a(n) = 3.at n=21A098408
• Length of the cycle for Lucas numbers mod 10^n.at n=7A114307
• a(n) is the minimal difference between two distinct n-digit numbers with property that when one of them is typed into a calculator and rotated 180 degrees, the other one is seen.at n=14A125521
• Numbers k such that k and k^2 use only the digits 0, 1, 3, 5 and 9.at n=36A136846
• Numbers k such that k and k^2 use only the digits 0, 1, 3 and 9.at n=16A136853
• Numbers k such that k and k^2 use only the digits 0, 2, 3, 7 and 9.at n=17A136895
• Numbers k such that k and k^2 use only the digits 0, 3, 4, 5 and 9.at n=23A136929
• Numbers k such that k and k^2 use only the digits 0, 3, 4, 7 and 9.at n=37A136934
• Numbers k such that k and k^2 use only the digits 0, 3, 4, 8 and 9.at n=29A136935
• Numbers k such that k and k^2 use only the digits 0, 3, 5, 7 and 9.at n=23A136940
• Numbers k such that k and k^2 use only the digits 0, 3, 5, 8 and 9.at n=39A136941
• Numbers k such that k and k^2 use only the digits 0, 3, 5 and 9.at n=10A136942
• Numbers k such that k and k^2 use only the digits 0, 3, 7, 8 and 9.at n=12A136947