21754

Appears in sequences

• a(n) = (5*n+1)*(5*n+4).at n=29A001545
• Self-convolution of composite numbers.at n=34A023648
• Table T(n,k) by antidiagonals. T(n,k) is the number of primitive (=aperiodic) k-ary words (n,k >= 1) with length less than or equal to n which are earlier in lexicographic order than any other word derived by cyclic shifts of the alphabet.at n=62A143327
• Triangle of coefficients of polynomials v(n,x) jointly generated with A210862; see the Formula section.at n=51A210863
• Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 801", based on the 5-celled von Neumann neighborhood.at n=27A273575
• Numbers k such that Fibonacci(k) == +-1 (mod k) and k is neither 1 nor prime nor twice a prime.at n=27A279072
• Number of primitive (=aperiodic) 4-ary words with length less than or equal to n which are earlier in lexicographic order than any other word derived by cyclic shifts of the alphabet.at n=7A320088