28448

Appears in sequences

• Ruth-Aaron numbers (2): sum of prime divisors of n = sum of prime divisors of n+1 (both taken with multiplicity).at n=30A039752
• Number of permutations in the symmetric group S_n such that the maximal cycle has length exactly 3.at n=9A071007
• Row sums of triangle A112500.at n=7A112501
• Triangle read by rows: T(n,k) is the number of permutations of n elements that have the longest cycle length k.at n=38A126074
• a(n) = OrdinaryUnitarySigma(a(n-1)).at n=13A126850
• Numbers k such that there is 1 prime between 100*k and 100*k + 99.at n=40A186393
• Number of (n+1)X(n+1) 0..3 symmetric matrices containing all values 0..3 with every 2X2 subblock having two, three or four distinct values, and new values 0..3 introduced in lower triangle row major order.at n=2A210824
• Number of 3 X 3 X 3 triangular 0..n arrays with every horizontal row nondecreasing, first elements of rows nonincreasing, last elements of rows nondecreasing, and every row having the same average value.at n=36A215183
• Number of defective 3-colorings of an n X 6 0..2 array connected horizontally, diagonally and antidiagonally with exactly two mistakes, and colors introduced in row-major 0..2 order.at n=2A229635
• T(n,k) = number of defective 3-colorings of an n X k 0..2 array connected horizontally, diagonally and antidiagonally with exactly two mistakes, and colors introduced in row-major 0..2 order.at n=30A229637
• Number of defective 3-colorings of a 3 X n 0..2 array connected horizontally, diagonally and antidiagonally with exactly two mistakes, and colors introduced in row-major 0..2 order.at n=5A229639
• Number of nX3 0..3 arrays with no element equal to zero plus the sum of elements to its left or zero plus the sum of elements above it or one plus the sum of the elements diagonally to its northwest, modulo 4.at n=6A240323
• T(n,k)=Number of nXk 0..3 arrays with no element equal to zero plus the sum of elements to its left or zero plus the sum of the elements above it or one plus the sum of the elements diagonally to its northwest, modulo 4.at n=38A240327
• T(n,k)=Number of nXk 0..3 arrays with no element equal to zero plus the sum of elements to its left or zero plus the sum of the elements above it or one plus the sum of the elements diagonally to its northwest, modulo 4.at n=42A240327
• Numerators of the rational convergents to the periodic continued fraction 1/(2 + 1/(7 + 1/(2 + 1/(7 + ...)))).at n=7A243470
• Numbers k such that (16*10^k + 197) / 3 is prime.at n=23A280205
• Number of interior points that are the intersections of exactly two chords in the configuration A006561(n).at n=31A292104
• Column 2 of triangle A318945.at n=12A318947
• The number of interior points that are intersections of exactly two chords for a 2n-gon where all its vertices are joined by lines (cf. A006561).at n=15A352144
• Number of unlabeled trees on n nodes with maximum degree three and three vertices of degree three.at n=19A355024