38781

Appears in sequences

• Triangular numbers with property that digits alternate in parity.at n=38A068882
• a(1) = 0, then smallest triangular number such that a(n+1)- a(n) is a palindrome.at n=26A075057
• Third row of Pascal-(1,6,1) array A081581.at n=40A081591
• Structured hexagonal diamond numbers (vertex structure 5).at n=30A100178
• Coefficients of x/(1-3*x-3*x^2-x^3).at n=9A108368
• Triangular numbers for which the sum of the digits is a cube.at n=13A117803
• (1/8)*number of lattice points with odd indices in a cubic lattice inside a sphere around the origin with radius 2*n.at n=41A120884
• Triangular numbers t such that t+10 is a prime.at n=35A129755
• a(n) = larger member of n-th pair of distinct, positive, triangular numbers whose sum and difference are also triangular numbers.at n=9A185128
• Triangular numbers of the form 2p-1 where p is prime.at n=36A217000
• The number of permutations of length n sortable by 2 prefix block transpositions.at n=20A228394