20868

Appears in sequences

• Perimeters of more than one primitive Pythagorean triangle.at n=37A024408
• A list of equal temperaments (equal divisions of the octave) whose nearest scale steps are closer and closer approximations to the six simple ratios of musical harmony: 6/5, 5/4, 4/3, 3/2, 8/5 and 5/3.at n=23A054540
• A list of equal temperaments (equal divisions of the octave) whose nearest scale steps are closer and closer approximations to four of the simple ratios of musical harmony: 5/4, 4/3, 3/2 and 8/5.at n=26A060525
• A list of equal temperaments (equal divisions of the octave) whose nearest scale steps are closer and closer approximations to the 7 pairs of complementary target ratios needed to express the 12 unsymmetrical steps of the untempered (Just Intonation) scale known as the Duodene: 3/2 and 4/3, 5/4 and 8/5, 6/5 and 5/3, 9/8 and 16/9, 10/9 and 9/5, 16/15 and 15/8 and 45/32 and 64/45.at n=32A061920
• A list of equal temperaments (equal divisions of the octave) whose nearest scale steps are closer and closer approximations to the 11 pairs of target ratios needed to express the 22 steps of the theoretical Hindu scale known as the 22 Srutis: 45/32 and 64/45, 27/20 and 40/27, 4/3 and 3/2, 81/64 and 128/81, 5/4 and 8/5, 6/5 and 5/3, 32/27 and 27/16, 9/8 and 16/9, 10/9 and 9/5, 16/15 and 15/8, 256/243 and 243/128.at n=42A061921
• Triangle arising from (4,2) tennis ball problem, read by rows.at n=34A078990
• Triangular array related to tennis ball problem, read by rows.at n=46A079521
• Triangle read by rows: T(n,k) is the number of alternating (i.e., down-up) permutations of {1,2,...,n} having k fixed points (n >= 0, 0 <= k <= ceiling(n/2)).at n=44A162979
• Triangle read by rows: T(n,k) is the number of reverse alternating (i.e., up-down) permutations of {1,2,...,n} having k fixed points (n >= 0, 0 <= k <= 1 + floor(n/2)).at n=47A162980
• Number of (n+2)X(n+2) 0..1 arrays with every 3X3 subblock diagonal median minus antidiagonal median nondecreasing horizontally, vertically and ne-to-sw antidiagonally.at n=1A253954
• Number of (n+2)X(2+2) 0..1 arrays with every 3X3 subblock diagonal median minus antidiagonal median nondecreasing horizontally, vertically and ne-to-sw antidiagonally.at n=1A253955
• T(n,k)=Number of (n+2)X(k+2) 0..1 arrays with every 3X3 subblock diagonal median minus antidiagonal median nondecreasing horizontally, vertically and ne-to-sw antidiagonally.at n=4A253961
• Number of (2+2)X(n+2) 0..1 arrays with every 3X3 subblock diagonal median minus antidiagonal median nondecreasing horizontally, vertically and ne-to-sw antidiagonally.at n=1A253962
• Guttmann-Torrie series coefficients rho_n*c_{n}^{2} for square lattice, with wedge angle Pi/2.at n=7A259802
• Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 145", based on the 5-celled von Neumann neighborhood.at n=32A270288
• Number of 2 X n 0..1 arrays with no element equal to more than one of its horizontal and antidiagonal neighbors, with the exception of exactly one element, and with new values introduced in order 0 sequentially upwards.at n=15A281206
• Number of permutations s_1,s_2,...,s_n of 1,2,...,n with s_n = 1 (if n>0) and such that for all j=1,2,...,n, Sum_{i=1..j} s_i divides Sum_{i=1..j} s_i^3.at n=14A291519
• G.f. A(x) satisfies: 1 = Sum_{n>=0} ( 3*(1+x)^n - A(x) )^n / 3^(n+1).at n=3A303653
• Numbers k such that the k-th composition in standard order is an alternating permutation of {1..k} for some k.at n=41A349051
• Viggo Brun's ternary continued fraction algorithm applied to { log 2, log 3/2, log 5/4 } produces a list of triples (p,q,r); sequence gives p values.at n=24A359742