20710

Appears in sequences

• a(1) = a(2) = 1, a(3) = 4; thereafter a(n) = a(n-1) + a(n-3).at n=25A001609
• Sum of 10 nonzero 8th powers.at n=34A003388
• Numbers that are the sum of 6 positive 9th powers.at n=9A003395
• Numbers that are the sum of at most 6 positive 9th powers.at n=42A004890
• a(n) = prime(n)*prime(n-1) - 1.at n=34A023515
• a(n) = (27*n^2 + 9*n + 2)/2.at n=39A093485
• Triangle read by rows: T(n,k) is the number of Motzkin paths of length n with k peaks (n>=0, 0<=k<=floor(n/2)).at n=59A097860
• Main diagonal of square array A137570.at n=6A137571
• Terms of A122782 which are not Carmichael numbers A002997.at n=39A153515
• Base 4 perfect digital invariants (written in base 10): numbers equal to the sum of the k-th powers of their base-4 digits, for some k.at n=34A162219
• Totally multiplicative sequence with a(p) = a(p-1) + 9 for prime p.at n=29A166706
• a(n) = n*(n+1)*(6*n-5)/2.at n=19A172082
• Lower Wythoff values for sequence A185615(n).at n=25A185616
• a(n) = n*(14*n + 13).at n=38A195028
• The number of integer partitions P of n such that either the length k of P is not a part or P has at least one part equal to 1 (or both).at n=37A229863
• Numbers x such that sigma(x) + sigma(R(x)) = sigma(x + R(x)), where R(x) is the digit reversal of x and sigma(x) is the sum of the divisors of x.at n=20A246487
• Numbers n such that n!3 + 3^2 is prime.at n=42A247865
• Number of strings of length n over a 10-letter alphabet that begin with a nontrivial palindrome.at n=5A249643
• Second partial sums of ninth powers (A001017).at n=2A253637
• a(n) = 2^(n+1) + 3^n + 3.at n=9A254028