122265

Appears in sequences

• Smaller of an amicable pair: (a,b) such that sigma(a) = sigma(b) = a+b, a < b.at n=14A002025
• Amicable numbers.at n=27A063990
• Triangular numbers T(k) that are three times another triangular number: T(k) such that T(k) = 3*T(m) for some m.at n=5A076140
• Triangular numbers whose largest proper divisor is also triangular.at n=6A076170
• a(1) = 1, a(n+1)= smallest triangular number greater than the n-th partial sum.at n=16A076971
• Determinant of the 2 X 2 matrices where the first column is consecutive triangular numbers and the second column is the corresponding consecutive Fibonacci numbers.at n=16A113772
• Partial sums of dodecahedral numbers (A006566).at n=18A116689
• Triangular numbers for which the sum of the digits equals the sum of the digits of the next triangular number.at n=23A117511
• Triangle T(n, k) = Sum_{j=0..n} (2*n)!/((2*n-k-j)!*j!*k!), read by rows.at n=25A141723
• Triangle, read by rows, T(n, k) = A059481(n,k)*(A059481(n,k) - 1)/2.at n=39A171379
• Conjectured list of smallest terms of k-sociable cycles of order r.at n=24A183016
• Triangular numbers that are the product of two triangular numbers greater than 1.at n=30A188630
• Numbers k such that sigma(k) = sigma(sigma(k)-k).at n=31A206708
• Smaller members of regular amicable pairs.at n=10A215491
• Triangular numbers that are the product of three distinct triangular numbers greater than 1.at n=21A225440
• Abundant numbers whose aliquot sequence is abundant, deficient, abundant, ..., etc.at n=19A234969
• The positions of records in A236747.at n=15A237267
• Amicable pairs.at n=28A259180
• Amicable pairs (x < y) ordered by nondecreasing sum (x + y) and then by increasing x.at n=30A259933
• Smaller of amicable pair (x, y) as they are listed in A259933.at n=15A260086