157248

Appears in sequences

• Number of invertible 2 X 2 matrices mod n.at n=25A000252
• a(n) = A027082(n, n+3).at n=15A027085
• Sum of two (possibly negative) cubes in at least 3 ways.at n=21A051383
• Numbers whose 4th power can be expressed as the sum of two positive cubes in more than one way.at n=34A051388
• a(n) is the sum of the divisors of Fibonacci(n) (A000045).at n=23A063477
• a(n) = a(n-1) - (n-1)*a(n-2), with a(0) = 1, a(1) = 2.at n=14A121966
• Amicable triples. Sequence gives sigma values: A125490(n) + A125491(n) + A125492(n).at n=8A137231
• Amicable triples. Sequence gives sigma values: A125490(n) + A125491(n) + A125492(n).at n=9A137231
• Consider numbers m,n such that UnitaryPhi(m)=UnitaryPhi(n)=3*(m*n)^(1/2)/4, m <= n; sequence gives values of n.at n=6A143649
• Numbers m,n such that UnitaryPhi(n)=UnitaryPhi(m)=3/4*(m*n)^(1/2), m<=n; sequence gives values of m.at n=6A143650
• Triangle read by rows: T(n, k) = (2^(n-k)*3^k + 2^k*3^(n-k))*binomial(n, k).at n=39A154692
• Triangle read by rows: T(n, k) = (2^(n-k)*3^k + 2^k*3^(n-k))*binomial(n, k).at n=41A154692
• The sum of the two numbers in an amicable pair, A002025(n) + A002046(n).at n=11A180164
• Numbers n with property that n and 2n are sums of two distinct positive cubes.at n=29A191345
• Integers n such that each of n, 2n and 3n is a sum of 2 distinct positive cubes.at n=7A191383
• Number of n X 5 0..1 arrays avoiding 0 0 1 and 0 1 0 horizontally and 0 0 1 and 1 1 0 vertically.at n=11A207388
• The sum (in nondecreasing order) of the two numbers in an amicable pair.at n=11A259953
• Numbers in A003325 whose 4th power is the sum of two positive cubes in a nontrivial way.at n=20A282872
• Irregular triangle read by rows: T(n, k) = number of ways to tile an n X n X n triangular area with k 2 X 2 X 2 triangular tiles and an appropriate number (= n^2-4*k) of 1 X 1 X 1 tiles.at n=41A286436
• Number of ways to tile an n X n X n triangular area with five 2 X 2 X 2 triangular tiles and an appropriate number (= n^2-20) of 1 X 1 X 1 tiles.at n=3A286440