27055

Appears in sequences

• Expansion of 1/((1-x)(1-3x)(1-6x)(1-9x)).at n=4A021504
• Number of permutations of length n which avoid the patterns 123 and 4312.at n=27A116699
• Number of binary arrays indicating the locations of trailing edge maxima of a random length-n 0..4 array extended with zeros and convolved with -1,2,-1.at n=18A222039
• Number of nX3 0..1 arrays with every element equal to 0, 1, 3 or 5 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.at n=12A302422
• a(n) is the smallest number which can be represented as the sum of n distinct nonzero n-gonal numbers in exactly n ways, or 0 if no such number exists.at n=16A350405
• Start with the list of positive integers 1,2,3,... . After each integer k, insert k empty positions. Fill these positions, from left to right, with the positive integers in order. Repeat this spacing-and-filling process indefinitely. The sequence consists of the positions of the last occurrence of 1 after each step.at n=7A391868