20979

Appears in sequences

• Smallest number of triangulations of n points in the plane.at n=11A063544
• Number of maximal triangulations (using all 2(n+2) points) of a convex polygon having (n+2) sides and an interior point in the middle of each side.at n=5A086452
• Numbers k such that both the k-th and (k+1)-th primes have the same sum of digits squared but different sets of digits.at n=6A109183
• Numbers n such that A112131(n) is a Harshad number and sets a new record for number of digits.at n=10A109463
• Triangle read by rows: T(n,k) is number of hex trees with n edges and k nonroot nodes of outdegree 2.at n=18A126183
• a(1) = 3, a(n) = round(a(n-1)*3/2) for n > 1, using round-to-even method.at n=22A147790
• a(n) is the smallest positive number such that a(n)*n is an anagram of a(n)*6.at n=11A175695
• Sequence defined by the recurrence formula a(n+1)=sum(a(p)*a(n-p)+k,p=0..n)+l for n>=1, with here a(0)=1, a(1)=3, k=0 and l=-1.at n=8A176749
• Numbers k such that 2^k + k^2 + 2 is prime.at n=17A177070
• Least number having n orderless representations as p^2 + q^2 + r^2, where p, q, and r are primes.at n=16A214512
• Sum of the two smallest parts from the partitions of 4n into 4 parts with smallest part = 1.at n=31A239059
• Number of partitions of n such that m(1) = m(3), where m = multiplicity.at n=49A240058
• Numbers n dividing every cyclic permutation of n^4.at n=27A242740
• Numbers m such that the result of prepending a zero digit to m, removing the least significant digit D, and prepending D, is divisible by m.at n=39A256005
• Duplicate of A063544.at n=11A276145
• T(n,k)=Number of nXk 0..1 arrays with no element equal to more than two of its horizontal, diagonal or antidiagonal neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards.at n=46A281563
• Number of 2Xn 0..1 arrays with no element equal to more than two of its horizontal, diagonal or antidiagonal neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards.at n=8A281564
• Number of nX5 0..1 arrays with every element unequal to 1, 2, 3 or 5 king-move adjacent elements, with upper left element zero.at n=5A304016
• Number of nX6 0..1 arrays with every element unequal to 1, 2, 3 or 5 king-move adjacent elements, with upper left element zero.at n=4A304017
• T(n,k)=Number of nXk 0..1 arrays with every element unequal to 1, 2, 3 or 5 king-move adjacent elements, with upper left element zero.at n=49A304019