20001

Appears in sequences

• Primes in ternary.at n=37A001363
• Cycle class sequence c(n) (the number of true cycles of length n in which a certain node is included) for zeolite RUT = RUB-10 R4[B4Si32O72] starting from a T2 atom.at n=13A019233
• n written in fractional base 4/2.at n=33A024630
• Numbers k such that k^2+k+2 is a palindrome.at n=22A027712
• Lexicographically earliest strictly increasing base 3 autovarious sequence: a(n) = number of distinct a(k) mod 3^n (written in base 3).at n=20A037091
• Numbers n with property that n is a substring of its base 5 representation.at n=11A038105
• Numbers whose sum of digits is 3.at n=30A052217
• Number of integers k not exceeding 2^n such that the cube of number of divisors [A000005(k)] is larger than k.at n=20A056764
• Numbers k such that k^2 contains only digits {0,1,4}, not ending with zero.at n=12A058413
• Numbers whose cubes contain more than half the same digit and do not end in 0.at n=40A060814
• Automorphic numbers: numbers k such that k^6 ends with k. Also m-morphic numbers for all m not congruent to 26 (mod 50) but congruent to 6 (mod 10).at n=33A068408
• Primes of form 4k+3 written in base 3.at n=19A072805
• To get a(n), write n in balanced ternary notation (using only digits -1, 0, 1, -1), then change -1's to 0's, 0's to 1's, and 1's to 2's.at n=42A072998
• a(1) = 2, then the smallest squarefree number greater than the previous term that begins with the end of the previous term.at n=10A077209
• Convoluted convolved Fibonacci numbers G_j^(10).at n=8A089097
• a(1) = 1 and a(n+1) is the least number > a(n) that begins with the last digit of a(n) and doesn't end with 0.at n=12A098752
• Greater of number pair whose squares are reversals of each other, with no leading zeros allowed.at n=27A106324
• Numbers k such that k and k^2 use only the digits 0, 1, 2 and 4.at n=58A136816
• a(n+1) is the least integer > a(n) containing all digits of a(n); a(1)=2.at n=17A155890
• a(n) = 50*n^2 + 1.at n=19A157916