19110

Appears in sequences

• Number of nonseparable tree-rooted planar maps with n + 2 edges and 3 vertices.at n=11A006411
• Number of 5's in all partitions of n.at n=38A024789
• 1 / min{1/n - 1/a - 1/b > 0}, where a and b are integers.at n=12A045470
• Composite numbers k such that the difference between the odd and even aliquot parts of k divides k.at n=23A066193
• Triangular numbers which are products of triangular numbers larger than 1.at n=22A068143
• Triangular numbers which are a concatenation of two or more positive triangular numbers.at n=28A068144
• Triangular numbers of the form 10*k.at n=38A069498
• Triangular numbers of the form 21*k.at n=37A069499
• Triangular numbers which are 6-almost primes.at n=15A076580
• Smallest triangular number divisible by exactly n triangular numbers.at n=10A076983
• a(n) = n^2 * (n^2 - 1)/2.at n=13A083374
• G.f. A(x) defined by: A(x)^8 consists entirely of integer coefficients between 1 and 8 (A083948); A(x) is the unique power series solution with A(0)=1.at n=7A084208
• a(n)=floor{square((1*n^0+1*n^1+2*n^2+4*n^3)/(1*n^0+2*n^1+1*n^2))}.at n=35A086863
• Triangle read by rows in which the n-th row contains the n smallest triangular numbers with the least significant digits of the n-th triangular number.at n=9A095225
• Diagonal of the triangle A095225.at n=3A095226
• Numbers k such that k^4 = x^3 + y^2 has an integer solution.at n=41A096741
• Matrix inverse of the Narayana triangle A001263.at n=31A103364
• Triangular numbers all of whose digits are nonprimes.at n=25A111484
• Hexagonal numbers for which the product of the digits is also a hexagonal number.at n=40A117063
• Triangular numbers for which the sum of the digits is a pentagonal number.at n=23A117305