37926

Appears in sequences

• Pentagonal pyramidal numbers: a(n) = n^2*(n+1)/2.at n=42A002411
• Even pentagonal pyramidal numbers.at n=31A015224
• Write cosec x = 1/x + Sum e_n x^(2n-1)/(2n-1)!; sequence gives denominators of e_n.at n=20A036283
• a(n) = 4n^3 + 2n^2.at n=20A089207
• k-imperfect numbers for some k >= 1.at n=15A127724
• 3-imperfect numbers.at n=8A127726
• Symmetrical Hahn weights on q-form factorials:m=2;q=3; q-form:t(n,m)=If[m == 0, n!, Product[Sum[(m + 1)^i, {i, 0, k - 1}], {k, 1, n}]]; Hahn weight:b(n,k,m)=If[n == 0, 1, (n!*t[m + 1, k]*t[m + 1, n - k])/(k!*(n - k)!*t[1, n])].at n=22A157321
• Symmetrical Hahn weights on q-form factorials:m=2;q=3; q-form:t(n,m)=If[m == 0, n!, Product[Sum[(m + 1)^i, {i, 0, k - 1}], {k, 1, n}]]; Hahn weight:b(n,k,m)=If[n == 0, 1, (n!*t[m + 1, k]*t[m + 1, n - k])/(k!*(n - k)!*t[1, n])].at n=26A157321
• a(n) = 1458*n + 18.at n=25A157505
• The sum of all the entries in an n X n Cayley table for multiplication in Z_n.at n=42A160255
• Pentagonal pyramidal numbers which are the sum of two other such numbers: A002411(k) = A002411(i)+A002411(j) with i,j>0.at n=0A172425
• Numbers divisible by at least five of their digits, different and >1.at n=4A187533
• Number of n X 5 0..1 arrays avoiding 0 0 1 and 1 0 0 horizontally and 0 0 1 and 1 0 1 vertically.at n=8A209647
• a(n) = n * A002445(n).at n=21A228838
• Pentagonal pyramidal numbers divisible by 3.at n=28A299412
• a(n) = n*(2*(n - 2)*n + (-1)^n + 3)/4.at n=43A323724
• a(n) is the sum of all products of pairs of numbers joined by the diagonals of an n-gon when its vertices are numbered from 1 to n in order.at n=23A337130
• a(n) = denominator(4^(n + 1)*zeta(-n, 1/4)).at n=41A344918
• a(n) = Sum_{k=1..n} sigma_2( n/gcd(k,n) ).at n=41A372226
• Triangular array read by rows: A063007 * A007318.at n=22A376467