69615

Appears in sequences

• Smaller of an amicable pair: (a,b) such that sigma(a) = sigma(b) = a+b, a < b.at n=11A002025
• Expansion of Molien series for 16-D extraspecial group 2^{1+2*4}.at n=6A030535
• a(n) is the least common multiple of {1, 5, 9, 13, 17, ..., 4n+1} (A016813).at n=5A051539
• Amicable numbers.at n=20A063990
• Numbers k such that both k and k+1 are abundant.at n=14A096399
• Denominator of 1 + 1/5 + 1/9 +...+ 1/(4n+1).at n=5A097328
• Numbers k such that both sigma(k) >= 2*k-1 and sigma(k+1) >= 2*(k+1)-1.at n=16A103289
• Minimal number of times a rectangular grid of n X n+1 elements can be slid along a 45-degree line before a rotated version of the initial grid appears.at n=11A110026
• Number of reduced words of length n in the Weyl group B_17.at n=6A161877
• Number of reduced words of length n in the Weyl group D_17.at n=6A162328
• Conjectured list of smallest terms of k-sociable cycles of order r.at n=21A183016
• Conjectured list of multisociable numbers.at n=33A183019
• Numbers k such that sigma(k) = sigma(sigma(k)-k).at n=24A206708
• Number of (w,x,y,z) with all terms in {0,...,n} and at least one of them is the range of {w,x,y,z}.at n=21A212746
• Smaller members of regular amicable pairs.at n=8A215491
• Abundant numbers whose aliquot sequence is abundant, deficient, abundant, ..., etc.at n=13A234969
• a(n) is the denominator of polygamma(2n+1, 1) / Pi^(2n+2).at n=23A255007
• Amicable pairs.at n=22A259180
• Amicable pairs (x < y) ordered by nondecreasing sum (x + y) and then by increasing x.at n=22A259933
• Smaller of amicable pair (x, y) as they are listed in A259933.at n=11A260086