18760

Appears in sequences

• Partial sums of A007587.at n=13A051799
• Number of polyhexes with n cells without holes that do not tile the plane.at n=9A070768
• Starting positions of strings of three 5's in the decimal expansion of Pi.at n=15A083620
• Pentagonal numbers (A000326) whose digit reversal is a prime.at n=19A115707
• Pentagonal numbers for which the sum of the digits is also a pentagonal number.at n=14A117709
• Pentagonal numbers for which both the sum of the digits and the product of the digits are pentagonal numbers.at n=7A117711
• Pentagonal numbers that are the sum of a nonzero pentagonal number and a nonzero square in at least one way.at n=41A134938
• a(n) = 4*(4 + 9*n^2 + 15*n).at n=22A144449
• Terms of A061039 that are multiple of 10, in the order in which they appear.at n=27A146762
• Number of 6X2 integer matrices with each row summing to zero, row elements in nondecreasing order, rows in lexicographically nondecreasing order, and the sum of squares of the elements <= 2*n^2 (number of collections of 6 zero-sum 2-vectors with total modulus squared not more than 2*n^2, ignoring vector and component permutations).at n=18A192706
• Array of coefficients of polynomials providing the third term of the numerator of the generating function for odd powers (2*m+1) of Chebyshev S-polynomials. The present polynomials are called P(m;2,x^2), m >= 2.at n=25A217479
• 26-gonal numbers: a(n) = n*(12*n-11).at n=40A255185
• Number of n X 3 arrays containing 3 copies of 0..n-1 with every element equal to or 1 greater than any north neighbor modulo n and the upper left element equal to 0.at n=9A267748
• Pentagonal numbers divisible by 4.at n=28A298397
• Denominators of (1/8)*n*(5 + 3*n)/((1 + 3*n)*(4 + 3*n)), n >= 0.at n=22A300297
• Square array A(n,k), n >= 1, k >= 1, read by antidiagonals, where A(n,k) is Sum_{j=1..n} binomial(j*k, k).at n=31A323663
• Triangle read by rows: T(n,k) is the number of n-bead necklaces using exactly k colors with no adjacent beads having the same color.at n=40A330618
• a(n) is the number of compositions of n, b_1 + ... + b_t = n such that sqrt(b_1 + sqrt(b_2 + ... + sqrt(b_t)...)) is an integer.at n=51A338271
• a(n) = Sum_{k=1..n} floor(n^3/k^3).at n=24A344675
• Pentagonal numbers that are abundant.at n=37A379264