21102

Appears in sequences

• Admirable Harshad numbers such that the subtracted divisor is also a Harshad number.at n=22A109396
• Admirable Harshad numbers n such that the subtracted divisor is equal to the digital sum of n.at n=13A111948
• Take the base-3 representation of n, render that in decimal notation and take the base-3 representation of n again.at n=18A126135
• Numbers n such that d(1)^1 + d(2)^2 + ... + d(p)^p and d(1)^p + d(2)^p-1 +... + d(p)^1 are squares, where d(i), i=1..p, are the digits of n.at n=42A178360
• Numbers 3*n + 2 written in base 3.at n=66A190642
• Number of ordered triples (w,x,y) with all terms in {-n,...-1,1,...,n} and -2<=w+x+y<=2.at n=38A211616
• Start with a square; at each stage add a square at each expandable vertex so that the ratio of the side of the squares at stage n+1 and at stage n is the golden ratio phi=0.618...; a(n) is the number of squares in a portion of the n-th stage (see below).at n=11A269965
• Start with the hexagonal tile of the Shield tiling and recursively apply the substitution rule. a(n) is the number of square tiles after n iterations.at n=8A298679
• Number of length-n ternary words having at most 5 palindromic subwords (including the empty word).at n=36A329023
• Negasemiternary (or NST) representation of n.at n=11A355904