42224

Appears in sequences

• Expansion of a modular function.at n=22A006707
• Expansion of 1/((1-x)^4*(1-x^2)^2).at n=25A028346
• Palindromes of the form k*(k+5).at n=6A028559
• Palindromes with exactly 7 prime factors (counted with multiplicity).at n=3A046333
• Numbers m that minimize | k /(k- EulerPhi(k)) - golden ratio phi | when k runs over all the numbers with the same number of digits as m.at n=13A065758
• Numbers k that divide the alternating sum sigma(1) - sigma(2) + sigma(3) - sigma(4) + ... + ((-1)^(k+1))*sigma(k).at n=13A067931
• a(1) = 1, a(n) = smallest nontrivial palindromic multiple of a(n-1). a(n) is not equal to a(n-1) or a concatenation of a(n-1) with itself.at n=6A083147
• a(1) = 1; a palindrome is included in the sequence if it has a prime signature that is different from all previous terms.at n=32A083433
• Smallest palindromic number with exactly n divisors, or 0 if no such number exists.at n=39A083753
• a(1) = 1; for n > 1, a(n) is the smallest number that is either a divisor or a multiple, in that priority (order), of a(n-1) such that it is a distinct palindrome not included earlier.at n=35A089337
• Least k such that k and digit reversal of k both have n divisors, or 0 if no such number exists.at n=39A090315
• a(0)=1, a(1)=4, a(n) = 10a(n-1) + a(n-2).at n=5A109109
• Expansion of x^9/((1-x)*(1-x^2)*(1-x^3))^2.at n=39A117485
• Biquadrateful (i.e., not biquadrate-free) palindromes.at n=25A133514
• Palindromic in bases 10 and 36.at n=34A250412
• E.g.f. satisfies A(x)^(A(x)^2) = 1/(1 - x*A(x)).at n=7A355767
• Number of rooted ordered trees with n internal nodes where each node has out-degree 0, 2, or 6.at n=5A380761