139128

Appears in sequences

• Alkane (or paraffin) numbers l(8,n).at n=29A005995
• Solution to a Diophantine equation: each term is a triangular number and each term + 1 is a square.at n=7A006454
• Number of reversible strings with n-1 beads of 2 colors. 5 beads are black. String is not palindromic.at n=28A032092
• Numerators of continued fraction convergents to sqrt(263).at n=11A041492
• Tritriangular numbers: a(n) = binomial(binomial(n,2),2) = n*(n+1)*(n-1)*(n-2)/8.at n=33A050534
• One half of binomial coefficients C(2*n-4,5).at n=14A053132
• Consider 2n tennis players; a(n) is the number of matches needed to let every possible pair play each other.at n=15A062346
• Ulam numbers such that 2*n is also an Ulam number.at n=22A068791
• Let p = n-th prime of the form 4k+3, take smallest solution (x,y) to the Pellian equation x^2 - p*y^2 = 1 with x and y >= 1; sequence gives value of x.at n=29A081231
• Numbers that can be expressed as the difference of the squares of primes in exactly eight distinct ways.at n=26A092004
• Triangular numbers which are the sum of distinct double factorials (A006882).at n=33A115650
• 279841n^2 - 165048n + 24335.at n=1A156843
• Triangular numbers that differ from a square by 1.at n=11A182334
• a(n) = lcm(n,n+1,n+2,n+3,n+4,n+5,n+6)/420.at n=30A189144
• Number of (w,x,y,z) with all terms in {0,...,n} and odd range.at n=22A212890
• Sequences A124174 and A006454 interlaced.at n=15A217278
• Triangular numbers representable as t*p, where t>1 is a triangular number, p>1 is a prime power (A025475).at n=6A221563
• Triangular numbers of the form p^k - 1, where p is a prime number and k >= 2.at n=5A225115
• Triangular numbers of the form p^2 - 1 where p is a prime.at n=3A227480
• Number of n-element subsets of [n+5] having an even sum.at n=29A282081