54545

Appears in sequences

• Numbers k such that k*(k+5) gives the concatenation of two numbers m and m-4.at n=10A116261
• Palindromes with consecutive digits that differ exactly by 1.at n=42A207954
• Palindromes of the form 4n + 1 that are divisible by 5.at n=36A256704
• Triangle read by rows: Number of ideals in Partial Brauer Monoid PB_n.at n=29A276773
• a(n) = a(n-2) + 2*a(n-3) for n >= 3, where a(0) = 2, a(2) = 4, a(3) = 5.at n=24A288668
• E.g.f.: exp(x/(1 + x + x^2)).at n=8A293571
• a(n) is the smallest positive integer which can be represented as the sum of n distinct nonzero tetrahedral numbers in exactly n ways, or -1 if no such integer exists.at n=29A360217