21422

Appears in sequences

• Cycle class sequence c(n) (the number of true cycles of length n in which a certain node is included) for zeolite FER = Ferrierite Na2Mg2[Al6Si30O72].18H2O starting with a T4 atom.at n=13A019132
• Numerators of continued fraction convergents to sqrt(978).at n=7A042892
• Coefficients of a polynomial used in calculation of A055913.at n=14A055916
• Sum of the numbers of unitary divisors of the binomial coefficients C(n,k), k=0..n.at n=47A103445
• Successive differences of A000990.at n=28A147766
• Number of 5 X 5 X 5 triangular nonnegative integer arrays, symmetric under 120 degree rotation, with all sums of an element and its neighbors <= n.at n=20A166213
• 3-comma numbers: n occurs in the sequence S[k+1]=S[k]+10*last_digit(S[k-1])+first_digit(S[k]) for three different splittings n=concat(S[0],S[1]).at n=23A166513
• Number of (w,x,y,z) with all terms in {0,...,n} and |w-x|+|x-y+|y-z|=n.at n=28A212904
• Numbers k such that 3^k + 2^k + 10 is prime.at n=20A219617
• Number T(n,k) of equivalence classes of ways of placing k 2 X 2 tiles in an n X 10 rectangle under all symmetry operations of the rectangle; irregular triangle T(n,k), n>=2, 0<=k<=5*floor(n/2), read by rows.at n=45A238586
• Numbers k such that (16*10^k - 91)/3 is prime.at n=24A274336
• G.f. A(x) satisfies: 0 = Sum_{n=-oo..+oo} (-1)^n * x^(2*n) * (A(x) - x^n)^n * (1 - x^n*A(x))^n.at n=9A363138