26796

Appears in sequences

• Doubly triangular numbers: a(n) = n*(n+1)*(n^2+n+2)/8.at n=21A002817
• a(0) = 2; for n >= 0, a(n+1) = a(n)*(a(n)+1)/2.at n=5A007501
• Denominators of continued fraction convergents to sqrt(923).at n=11A042785
• Second partial sums of A001891.at n=13A053809
• a(n) = B(n)*C(n), where B(n) are Bell numbers (A000110) and C(n) are Catalan numbers (A000108).at n=6A064299
• Triply triangular numbers.at n=6A064322
• Quadruply triangular numbers.at n=3A066370
• Triangular numbers which are products of triangular numbers larger than 1.at n=26A068143
• z-value of the solution (x,y,z) to 5/n = 1/x + 1/y + 1/z satisfying 0 < x < y < z and having the largest z-value. The x and y components are in A075249 and A075250.at n=30A075251
• Triangular numbers which are 6-almost primes.at n=19A076580
• Triangular numbers that are 7 times triangular numbers.at n=4A077400
• Even numbers k such that the central binomial coefficient A000984(k, k/2) is divisible by k^2.at n=17A080395
• Starting positions of strings of three 7's in the decimal expansion of Pi.at n=29A083631
• a(n) = A000217(A000041(n)).at n=16A086737
• Numbers k such that 2^k - 1 is divisible by (k-1).at n=24A087965
• Least nontrivial n-tuply triangular number.at n=4A096662
• Largest denominator of greedy Egyptian fraction sum for M/N.at n=31A100140
• Triangle, read by rows, equal to the matrix inverse of A056241, which is formed from the even-indexed trinomial coefficients.at n=31A104027
• Numbers n such that sigma(n) = 12*phi(n).at n=5A104902
• Triangular numbers that are sums of two consecutive primes.at n=27A111163