30135

Appears in sequences

• INVERTi transform of A000081 = [1, 2, 4, 9, 20, 48, 115, 286, 719, 1842, 4766, 12486,...].at n=14A051573
• Triangle T(n,k) of series-reduced (or homeomorphically irreducible) labeled graphs with n nodes and k edges, k=0..binomial(n,2).at n=52A060514
• a(1) = 1; a(n) is the smallest triangular number > a(n-1) which differs from it at every digit.at n=30A068855
• Triangular numbers whose digit permutations yield at least two further triangular numbers.at n=19A069674
• Smallest triangular number with value of the internal digits = n; or 0 if no such number exists.at n=13A069692
• Triangular numbers which are also happy numbers (cf. A007770).at n=38A076712
• Smaller of the two successive triangular numbers which differ in the use of only one digit.at n=40A077759
• Triangular numbers for which the sum of the digits is a pentagonal number.at n=25A117305
• Partial sum of A005915.at n=13A126274
• Triangular numbers t which are average of two consecutive primes p and p+4.at n=26A129752
• Triangle read by rows, n>=1, 1<=k<=n, T(n,k) = k*binomial(n,k)^3*(n^2+n-k*n-k+k^2)/((n-k+1)^2*n).at n=23A202409
• Triangle read by rows, n>=1, 1<=k<=n, T(n,k) = k*binomial(n,k)^3*(n^2+n-k*n-k+k^2)/((n-k+1)^2*n).at n=25A202409
• Numbers with the property that in their factorization over distinct terms of A050376, the sums of prime and nonprime terms of A050376 are equal.at n=23A241270
• 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=28A254957
• Numbers n such that there are precisely 12 groups of orders n and n + 1.at n=0A298429
• Numbers that start a run of four consecutive triangular numbers with four distinct prime factors.at n=7A349773
• Number of integer compositions of n whose leaders of strictly increasing runs are distinct.at n=25A374687
• Table T(r,s) read by rows: the coefficient of [k^s] of the Wynn's r-th converging polynomial p_r(k) of Weber functions, 0<=s<=r.at n=49A380169
• Semiperimeter of the unique primitive Pythagorean triple (a,b,c) such that (a-b+c)/2 is A000032(n) and such that its long leg and its hypotenuse are consecutive natural numbers.at n=10A382409