100320

Appears in sequences

• Number of walks on cubic lattice.at n=19A005571
• Positive numbers k such that k and 3*k are anagrams in base 5 (written in base 5).at n=13A023062
• 5-Smith numbers.at n=17A103126
• Numbers with prime factorization pqrst^5.at n=9A190383
• Even 9-gonal (nonagonal) pyramidal numbers.at n=32A218329
• Integer areas A of integer-sided cyclic quadrilaterals such that the circumradius is of prime length.at n=28A230136
• Number of Dyck paths of semilength n such that no positive level has fewer than six peaks.at n=19A288682
• Pythagorean triples (X, Y, Z) that are the componentwise products of 2 primitive Pythagorean triples (x,y,z) and (r,s,t), that is, X=x*r, Y=y*s, ordered by increasing Z.at n=19A340790
• Positions of records in A357299: integers m such that the number of divisors whose first digit equals the first digit of m sets a new record.at n=12A355592
• a(n) is the smallest number m with exactly n divisors whose first digit equals the first digit of m.at n=28A357300
• a(n) = Sum_{k=0..floor(n/2)} binomial(n,k) * binomial(3*k,n-2*k).at n=11A389060
• Expansion of g^2/(1 - x*g)^4, where g = 1+x*g^3 is the g.f. of A001764.at n=7A391173