21641

Appears in sequences

• Expansion of (1-x)/(1-2*x-x^2-2*x^3).at n=11A077996
• Positive integers of the form (18*m^2+1)/11.at n=20A113338
• Numbers n with property that for each single digit d of n, we can also see the decimal expansion of 2^d as a substring of n. Also n may not contain any zero digits.at n=14A135016
• Numbers which converge to 2592 under repeated application of the powertrain map of A133500.at n=19A135384
• Numbers k that divide the sum of digits of 13^k.at n=41A175525
• Number of 5X2 integer matrices with each row summing to zero, row elements in nondecreasing order, rows in lexicographically nondecreasing order, and the sum of squares of the elements <= 2*n^2 (number of collections of 5 zero-sum 2-vectors with total modulus squared not more than 2*n^2, ignoring vector and component permutations).at n=23A192705
• Numbers n such that A003146(n) = floor(alpha^3*n)+1, where alpha = 1.839... is the positive real zero of x^3-x^2-x-1.at n=24A278353
• Decimal representation of the x-axis, from the origin to the right edge, of the n-th stage of growth of the two-dimensional cellular automaton defined by "Rule 533", based on the 5-celled von Neumann neighborhood.at n=15A282957
• Nonsemiprimes in A306097 = A121707 \ A267999.at n=29A321488