401401

Appears in sequences

• Pseudoprimes to bases 2 and 5.at n=30A083732
• Devaraj numbers: squarefree r-prime-factor (r>1) integers N=p1*...*pr such that phi(N)=(p1-1)*...*(pr-1) divides gcd(p1-1,...,pr-1)^2*(N-1)^(r-2).at n=32A104016
• Devaraj numbers (A104016) which are not Carmichael numbers.at n=3A104017
• Pseudoprimes (base-2) equal to product of 4 primes not necessarily distinct.at n=25A112441
• Number of base 21 circular n-digit numbers with adjacent digits differing by 7 or less.at n=5A125433
• G.f. satisfies: A(x) = exp( Sum_{n>=1} [A(x)^n + 1/A(-x)^n]*x^n/n ).at n=10A171191
• Numbers in A191311 but not in A129521.at n=19A191592
• Intersection of A001567 and A212502.at n=16A212601
• Heptagonal numbers which are products of four distinct primes.at n=32A351867