38415

Appears in sequences

• Expansion of (1-x)/(1-2*x-x^3+x^4).at n=15A052540
• Positive numbers which are one less than a perfect square that is also another power.at n=17A062965
• Numbers k such that sigma(k^2-k-1) = k*(k+1).at n=35A069826
• Numbers whose set of base 14 digits is {0,D}, where D base 14 = 13 base 10.at n=15A097260
• Primitive elements of A065607.at n=21A120692
• Elements of A065607 from primitive triples.at n=34A120693
• a(n) = n^4 - 1.at n=13A123865
• n^4 - 1 divided by its largest fourth power divisor.at n=12A128251
• Positive integers k such that there is no m different from k where both d(k) = d(m) and d(k+1) = d(m+1), where d(k) is the number of positive divisors of k.at n=37A161460
• a(n) = (8*n+3)*(8*n+5).at n=24A177065
• Numbers n such that n+(n+1), n^2+(n+1)^2, n+(n+1)^2, n^2+(n+1) are all prime.at n=36A216270
• a(n) gives the odd leg of the second of the two Pythagorean triangles with hypotenuse A080109(n) = A002144(n)^2. This is the larger of the two possible odd legs.at n=20A253804
• Variation on Fermat's Diophantine m-tuple: 1 + the GCD of any two distinct terms is a square.at n=24A274697
• Least common multiple of 7*n+1 and 7*n-1.at n=28A282286
• Bases in which 7 is a unique-period prime.at n=47A306075
• Numbers k such that k and k+1 are both phi-practical numbers (A260653).at n=40A330871
• Numbers of the form 16n^2 + 32n + 15 for which the central region of its symmetric representation of sigma consists of two subparts of sizes 4n+7 and 4n+1, n>=0.at n=39A335574
• a(n) is the number of numbers k such that A340873(k) = n.at n=34A341218
• Squarefree integers k such that x^4 - k*y^2 = 1 has a nontrivial solution.at n=40A356496
• Odd numbers that are one less than the square of a perfect power.at n=9A389956