20008

Appears in sequences

• Even octagonal numbers: a(n) = 4*n*(3*n-1).at n=41A014642
• Numbers whose base-7 representation contains exactly four 2's.at n=31A043404
• Number of ways to color vertices of a pentagon using <= n colors, allowing only rotations.at n=10A054620
• Number of n-bead necklaces with 10 colors.at n=5A054629
• T(n,k) = Sum_{d|k} phi(d)*n^(k/d)/k, triangle read by rows, T(n,k) for n >= 1 and 1 <= k <= n.at n=49A054630
• Intrinsic 10-palindromes: n is an intrinsic k-palindrome if it is a k-digit palindrome in some base.at n=17A060947
• Numbers n such that 2*n*k(n) is rational but not an integer, where k(n) is sum of successive remainders when computing the Euclidean algorithm for (1, 1/sqrt(n)) as defined in A086378 (MuPAD program is given there); numbers belonging to A086378 but not to A088900.at n=12A087414
• List the positions of all digits '1' in the sequence. This is the lexicographically earliest increasing sequence with this property.at n=46A098645
• Octagonal numbers for which the product of the digits is also an octagonal number.at n=35A117083
• a(n) = (a(n-1) + a(n-4))/gcd(a(n-1), a(n-4)) with a(1) = a(2) = a(3) = a(4) = 1.at n=52A214652
• Alternating sum of centered heptagonal pyramidal numbers.at n=32A270694
• Number x = concat(MSD(x),b) such that MSD(x)*b = d(x), where MSD(x) is the Most Significant Digit of x and d(x) is the number of divisors of x.at n=8A291618
• Expansion of Product_{n>=1} (1 + (4*x)^n)^(1/2).at n=7A298994
• The number of overpartitions of n whose Frobenius symbols have only positive parts in the top row.at n=27A347207
• Centered 27-gonal numbers.at n=38A389797