26240

Appears in sequences

• a(n) = s(n+3)/3, where s is A024961.at n=10A024962
• Numbers n such that n^1024 + 1 is prime (a generalized Fermat prime).at n=29A057002
• At stage 1, start with a unit equilateral equiangular triangle. At each successive stage add 3*(n-1) new triangles around outside with edge-to-edge contacts. Sequence gives number of triangles (regardless of size) at n-th stage.at n=38A064412
• a(n) = n*phi(n*phi(n)).at n=40A078774
• Structured triakis octahedral numbers (vertex structure 4).at n=19A100171
• Triangle of the elementwise product of binomial coefficients with q-binomial coefficients [n,k] for q = 3.at n=37A157640
• Consider the base-3 Kaprekar map n->K(n) defined in A164993. Sequence gives numbers belonging to cycles, including fixed points.at n=17A164998
• Consider the base-3 Kaprekar map n->K(n) defined in A164993. Sequence gives numbers belonging to cycles of length greater than 1.at n=12A165000
• Consider the base-3 Kaprekar map n->K(n) defined in A164993. Sequence gives least elements of each cycle, including fixed points.at n=10A165002
• Consider the base-3 Kaprekar map n->K(n) defined in A164993. Sequence gives least elements of each cycle of length > 1.at n=5A165004
• Consider the base-3 Kaprekar map x->K(x) described in A164993. Sequence gives the smallest number that belongs to a cycle of length n under repeated iteration of this map, or -1 if there is no cycle of length n.at n=3A165008
• Smallest member of cycle corresponding to n-th term of A165009.at n=10A165010
• Positive integers with the property that if the base-3 representation is reversed the result is twice the original number.at n=10A173951
• a(1)=32 and, for n > 1, a(n) = 9*a(n-1) + 32.at n=3A173952
• Numbers n such that phi(n)/n = 16/41.at n=13A176598
• Numbers with prime signature {7,1,1}, i.e., of form p^7*q*r with p, q and r distinct primes.at n=35A179696
• Number of (n+1)X7 0..1 arrays with the number of rightwards and downwards edge increases in each 2X2 subblock differing from the number in all its horizontal and vertical neighbors.at n=12A205070
• Number of (n+1) X (5+1) 0..1 arrays with every 2 X 2 subblock ne-sw antidiagonal difference nondecreasing horizontally and nw+se diagonal sum nondecreasing vertically.at n=8A258551
• a(n) = 4*(3^n-1).at n=8A302507
• Totients t such that the number of divisors of t equals the number of solutions of phi(x) = t.at n=25A305058