1186570

Appears in sequences

• a(n+1) = a(n)*(a(n)+1)/2.at n=4A013589
• Largest triangular number less than or equal to sum of previous terms with a(0)=1.at n=22A061883
• Triply triangular numbers.at n=10A064322
• Quadruply triangular numbers.at n=4A066370
• Let T(n) be the n-th triangular number n*(n+1)/2; then a(n) = n-th iteration T(T(T(...(n)))).at n=4A099129
• Tree generated by the triangular numbers: a(1) = 1; a(2n) = nontriangular(a(n)), a(2n+1) = triangular(a(n+1)), where triangular = A000217, nontriangular = A014132.at n=48A183079
• If x is in the sequence then so are x^2 and x(x+1)/2.at n=42A241241
• Triangular numbers which are products of six distinct primes.at n=17A362758
• Triangular numbers with tetrahedral indices: a(n) = (1/72) * (n*(n+1)*(n+2)*(n+3)*(n^2+2)).at n=20A373733