18183

Appears in sequences

• Molien series for Hecke group H_{3,4}.at n=21A027631
• Values of A038005 ending in 3.at n=21A038013
• Odd numbers in sorted order from generation 2 onwards.at n=31A048462
• Composite numbers k such that sigma(k)*(phi(k) + 2) is a square.at n=28A065655
• a(n) = floor(8^n/3^n).at n=10A094976
• Sub-Kaprekar numbers: k such that k = |q - r| and k^2 = q*10^m + r, for some m >= 1, q >= 0, 0 <= r < 10^m, with k not a power of 10.at n=12A118936
• Sub-Kaprekar numbers (2): n such that n=r-q and n^2=q*10^m+r, for some m>=1, q>=0, 0<=r<10^m, with n not a power of 10.at n=4A118938
• Eleven times hexagonal numbers: a(n) = 11*n*(2*n-1).at n=29A154617
• Triangle read by rows: T(n,k) = round(c(n)/(c(k)*c(n-k))) where c are partial products of a sequence defined in comments.at n=59A172358
• Triangle read by rows: T(n,k) = round(c(n)/(c(k)*c(n-k))) where c are partial products of a sequence defined in comments.at n=61A172358
• Unabridged sub-Kaprekar numbers (A118936, but allowing powers of ten).at n=16A228381
• Triangular array read by rows: row n shows the coefficients of the polynomial u(n) = c(0) + c(1)*x + ... + c(n)*x^(n) which is the denominator of the n-th convergent of the continued fraction [k, k, k, ... ], where k = (x + 2)/(x + 1).at n=49A231733
• Products p*q*r*s of distinct primes for which (p*q*r*s - 1)/2 is prime.at n=38A234498
• Numbers k of the form a - b + c, such that k^3 equals the decimal concatenation a//b//c and numbers k, b, and c have the same number of digits.at n=19A259379
• Numbers k of the form abs(a - b + c - d) such that k^4 equals the concatenation of a//b//c//d and numbers k,b,c,d have the same number of digits.at n=21A260193
• Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 549", based on the 5-celled von Neumann neighborhood.at n=25A272844
• Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 805", based on the 5-celled von Neumann neighborhood.at n=24A273604
• Numbers k such that sigma(k) = sigma(k+19), where sigma(k) is the sum of the divisors of k.at n=13A321533
• Number of polyforms with n cells on the faces of a deltoidal icositetrahedron up to rotation and reflection.at n=13A383804