21007

Appears in sequences

• "Real rabbits": a(n) = Re(c(n)) where complex c(n) = a(n) + i*b(n) and c(0) = i, c(1) = -i, c(n) = c(n-1) + i*c(n-2).at n=32A058184
• Number of n X n symmetric 0..6 arrays with rows, considered as 7-ary numbers, in nondecreasing order.at n=2A162082
• Number of (n+2)X(n+2) 0..2 arrays with every 3X3 subblock commuting with each horizontal and vertical neighbor 3X3 subblock.at n=4A186559
• Number of (n+2) X 7 0..2 arrays with every 3 X 3 subblock commuting with each horizontal and vertical neighbor 3 X 3 subblock.at n=4A186564
• Numbers n such that uphi(n) = uphi(n+1), where uphi(n) is the unitary totient function (A047994).at n=28A287055
• Record values in A317826.at n=15A317828
• Number of nX3 0..1 arrays with every element unequal to 2, 3, 4 or 6 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.at n=8A320359
• T(n,k)=Number of nXk 0..1 arrays with every element unequal to 2, 3, 4 or 6 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.at n=57A320364
• Regular triangle read by rows: T(n,k) is the k-th ionization energy of the n-th chemical element (in kJ/mol), rounded to the nearest integer.at n=9A322834
• Numbers k such that iphi(k) = iphi(k+1), where iphi(k) is an infinitary analog to the Euler totient function (A091732).at n=25A326403
• a(n) is the row of the Trithoff (tribonacci) array that contains the tails of the sequence which is n times the tribonacci numbers.at n=26A351685
• Numbers k such that A384247(k) = A384247(k+1).at n=34A385743