71780

Appears in sequences

• Consider the sequence of 4-tuples {0,a,b,c} (c>=a+b; a,b,c>0) which have the smallest integer 'c' required to reach {k,k,k,k} in n steps under map {r,s,t,u}->{|r-s|,|s-t|,|t-u|,|u-r|}. This sequence gives the third term 'b' of these quadruples.at n=30A034804
• Number of ways to toss a coin n times and not get a run of four.at n=18A135491
• a(n) = 5*(3*n+1)*(9*n+8)/2 (n>=0).at n=32A304508
• First differences of A000213, also twice A000073.at n=20A354784