21512

Appears in sequences

• Numbers k such that k, k+1, k+2 and k+3 have the same number of divisors.at n=31A006601
• Cubeful (i.e., not cubefree) palindromes.at n=34A035133
• Base-10 palindromes that start with 2.at n=37A043037
• Palindromic and divisible by 8.at n=25A045643
• Palindromes k such that the sum of the first palindromes up to k is a palindrome.at n=6A046487
• Palindromic untouchable numbers.at n=24A048187
• Expansion of 1/((1-x)^2*(1-x^2)^2*(1-x^3)*(1-x^4)^2*(1-x^5)).at n=27A069957
• Palindromic numbers with property that sum of digits is prime and number of prime digits is prime.at n=31A093807
• n+prime(n)+prime(prime(n)) is a triangular number, where prime(n) is the n-th prime.at n=20A116010
• Palindromic primes in base 7 (written in base 7).at n=19A117702
• Least K such that K*(prime(100*n)^(100*n))-1 is prime with prime(n)=n-th prime.at n=24A129245
• Numbers k such that k^3 divides 15^(k^2) - 1.at n=41A177915
• Number of nondecreasing arrangements of 6 numbers x(i) in -(n+4)..(n+4) with the sum of sign(x(i))*x(i)^2 zero.at n=20A188006
• Number of n X n arrays of the minimum value of corresponding elements and their horizontal or diagonal neighbors in a random, but sorted with lexicographically nondecreasing rows and nonincreasing columns, 0..3 n X n array.at n=3A219932
• Number of nX4 arrays of the minimum value of corresponding elements and their horizontal or diagonal neighbors in a random, but sorted with lexicographically nondecreasing rows and nonincreasing columns, 0..3 nX4 array.at n=3A219935
• T(n,k)=Number of nXk arrays of the minimum value of corresponding elements and their horizontal or diagonal neighbors in a random, but sorted with lexicographically nondecreasing rows and nonincreasing columns, 0..3 nXk array.at n=24A219939
• Number of 4Xn arrays of the minimum value of corresponding elements and their horizontal or diagonal neighbors in a random, but sorted with lexicographically nondecreasing rows and nonincreasing columns, 0..3 4Xn array.at n=3A219942
• Palindromes m such that m*(sum of digits of m) is also a palindrome.at n=31A229805
• Number of SAWs crossing a square domain of the hexagonal lattice.at n=3A354511
• Expansion of Sum_{k>0} x^(4*k)/(1-x^k)^5.at n=27A363608