147312

Appears in sequences

• Tetranacci numbers: a(n) = a(n-1) + a(n-2) + a(n-3) + a(n-4) for n >= 4 with a(0) = a(1) = a(2) = 0 and a(3) = 1.at n=22A000078
• Sigma unitary-sigma perfect numbers: numbers m which satisfy the following equation for some integer k: sigma(usigma(m)) = k*m where usigma(m) is sum of unitary divisors of m.at n=30A083288
• a(n)=the sum of the (1,2)- and (1,3)-entries and twice the (1,4)-entry of the matrix P^n + T^n, where the 4 X 4 matrices P and T are defined by P=[0,1,0,0;0,0,1,0;0,0,0,1;1,0,0,0] and T=[0,1,0,0;0,0,1,0;0,0,0,1;1,1,1,1].at n=20A109525
• a(n) = (9/2)*(n-1)*(n-2)*(n-3).at n=33A134171
• a(n) is the smallest tetranacci number (A000078) with exactly n prime factors (counted with multiplicity).at n=9A359877
• Number of compositions (ordered partitions) of n into parts not greater than sqrt(n).at n=19A364526
• Numbers m such that A188999(A034448(m)) = k*m for some k, where A034448 and A188999 are respectively the unitary and the bi-unitary sigma function.at n=42A369205