55777

Appears in sequences

• Numbers k such that the continued fraction for sqrt(k) has odd period and if the last term of the periodic part is deleted the two central terms are both 52.at n=2A031640
• Concatenation of n in base 2 up to base 10 and n in base 10 down to base 2 is prime, all numbers are interpreted as decimals.at n=11A054258
• a(n) = n^2*(2*n^2 + 1)/3.at n=17A071270
• Pentagonal numbers (A000326) whose digit reversal is the product of 2 palindromes greater than 1.at n=21A115703
• Pentagonal numbers with only odd digits.at n=15A117985
• a(n) = 128*n^2 - 32*n + 1.at n=20A157331
• a(n) = 128*n^2 + 2528*n + 12481.at n=10A157436
• a(n) = 2*prime(n)^2 - 1.at n=38A179262
• Number of arrays of 2n nondecreasing integers in -3..3 with sum zero and equal numbers greater than zero and less than zero.at n=31A203286
• Number of ways to cut an n X n square into squares with integer sides, reduced for symmetry, where the orbits under the symmetry group of the square, D4, have 8 elements.at n=6A226981
• Numbers k with digits 5 and 7 only.at n=37A284380
• Numbers k such that sigma((k + 1) / 2) is a prime q.at n=17A292446
• The first of two consecutive pentagonal numbers the sum of which is equal to the sum of two consecutive primes.at n=4A298463
• E.g.f. A(x) satisfies: A(x) = Sum_{n>=0} ( x^n + x*A(x) )^n / n!.at n=6A356772