30628

Appears in sequences

• Ramanujan's approximation to population of x^2 + y^2 <= 2^n.at n=17A000691
• Degrees of irreducible representations of Thompson group Th.at n=5A003916
• Triangular numbers whose digit permutations yield at least two further triangular numbers.at n=20A069674
• a(1) = 1, a(n+1)= smallest triangular number greater than the n-th partial sum.at n=14A076971
• Smaller of the two successive triangular numbers which differ in the use of only one digit.at n=41A077759
• A123689 based sequence as SO(A123689(n)) dimensions.at n=17A131513
• Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 0), (-1, 1, -1), (0, 1, 1), (1, -1, -1)}.at n=12A148049
• a(n) = larger member of n-th pair of distinct, positive, triangular numbers whose sum and difference are also triangular numbers.at n=8A185128
• Triangular numbers which have one or more occurrences of exactly five different digits.at n=19A241788
• Triangular numbers n with digits d_1, d_2, ..., d_k such that d_1*(d_1+1)/2 + ... + d_k*(d_k+1)/2 is a triangular number.at n=29A254957
• The intersection of hexagonal numbers (A000384) and centered 9-gonal numbers (A060544).at n=41A272399
• Triangular numbers that are repdigits with length > 2 in some base.at n=22A274084
• Triangular numbers of the form k^2 + 3.at n=3A328791
• Semiperimeter of the unique primitive Pythagorean triple whose inradius is A000032(n) and such that its long leg and its hypotenuse are consecutive natural numbers.at n=10A380823