1021735

Appears in sequences

• Alkane (or paraffin) numbers l(12,n).at n=16A018213
• a(n) = C(n)*(C(n)-1)/2, where C(n) are the Catalan numbers (A000108).at n=8A051789
• Least triangular number whose digit permutations yield exactly n further triangular numbers.at n=7A095870
• Smallest triangular number with exactly n anagrams that are triangular numbers.at n=6A166596
• Number of n-element subsets of [n+9] having an even sum.at n=16A282085
• Maximum over 0 <= k <= n/2 of the number of permutations of two symbols occurring k and n-2*k times, respectively, where a permutation and its reversal are counted only once.at n=34A362260