29890

Appears in sequences

• Triangular numbers with sum of digits = 28.at n=4A068132
• Triangular numbers with property that digits alternate in parity.at n=33A068882
• Triangular numbers which are the sum of two squares.at n=34A073613
• Triangular numbers which are also happy numbers (cf. A007770).at n=37A076712
• Row sums of triangle A093922.at n=17A093925
• Smith triangular numbers.at n=10A098840
• Numbers k such that lambda(k) = lambda(k+1).at n=26A173695
• a(n) = n*Pell(n) * Sum_{d|n} 1/(d*Pell(d)) where Pell(n) = A000129(n).at n=9A203414
• Number of 4-tuples (w,x,y,z) with all terms in {1,...,n} and w*x<=3*y*z.at n=14A211812
• a(n) is the number of nonnegative integers that can be represented in a 7-segment display by using only n segments (version A063720).at n=21A343314
• Numbers that start a run of four consecutive triangular numbers with four distinct prime factors.at n=6A349773
• Irregular triangle read by rows: T(n,k) is the number of essential graphs with n nodes and k (directed or undirected) edges (n >= 1, 0 <= k <= n*(n-1)/2).at n=37A368569