20251

Appears in sequences

• Expansion of 1/((1-3*x)*(1-5*x)*(1-9*x)).at n=4A017897
• Molien series for 3-D group R4.at n=19A037243
• Numbers k such that k^14 == 1 (mod 15^3).at n=24A056087
• Number of effective multiple alignments of three equal-length sequences.at n=4A124435
• Numbers k such that the sum of the digits of k^2 is 10. Multiples of 10 are omitted.at n=18A135027
• Numbers k such that k and k^2 both have digit sum 10. Multiples of 10 are omitted.at n=6A135029
• Triangle read by rows: T(n,k) is the number of n-Dyck paths containing k odd-length descents to ground level (0<=k<=n).at n=67A143949
• a(n) = 6n^3 + 1, solution z in Diophantine equation x^3 + y^3 = z^3 - 2. It may be considered a Fermat near miss by 2.at n=14A163827
• Number of permutations of 4 copies of 1..n avoiding adjacent step pattern up, up.at n=3A177637
• 15-gonal (or pentadecagonal) pyramidal numbers: a(n) = n*(n+1)*(13*n-10)/6.at n=21A177890
• Number of distinct finite languages over 4-ary alphabet, whose minimum regular expression has reverse Polish length 2n-1.at n=4A211946
• Numbers k such that the sum of digits of k^2 is 10.at n=45A262713
• a(n) = (a(n-1)^2+a(n-2)^2+a(n-3)^2+a(n-4)^2+a(n-1)*a(n-2)+a(n-1)*a(n-3)+a(n-1)*a(n-4)+a(n-2)*a(n-3)+a(n-2)*a(n-4)+a(n-3)*a(n-4))/a(n-5) with five initial ones.at n=7A276131
• Greatest integer k such that k/2^n < 1/phi, where phi = (1+sqrt(5))/2 = golden ratio.at n=15A293322
• Number of nX4 0..1 arrays with every element equal to 0, 2, 4, 5 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.at n=26A303321
• Numbers k such that sum of digits (k) and sum of digits (k^2) is 10.at n=17A325451
• Square array T(n,k), n >= 0, k >= 0, read by antidiagonals, where T(n,k) = Sum_{j=0..n} (-1)^(n-j) * multinomial(n+(k-1)*j; n-j, {j}^k).at n=32A336169
• Number of regions formed when n equally spaced points are placed around a circle and all pairs of points are joined by an interior arc whose radius equals the circle's radius.at n=24A371253