21088

Appears in sequences

• Number of partitions in parts not of the form 23k, 23k+3 or 23k-3. Also number of partitions with at most 2 parts of size 1 and differences between parts at distance 10 are greater than 1.at n=41A035991
• Intrinsic 10-palindromes: n is an intrinsic k-palindrome if it is a k-digit palindrome in some base.at n=21A060947
• Numbers k such that k*2^m-1 are composites for all exponents m in the range 0<=m<=k.at n=39A061154
• Sum of the first n safe primes.at n=33A066869
• Numbers n such that n^24 + 1 = p*q with p,q distinct primes.at n=33A119982
• Number of -n..n arrays x(0..6) of 7 elements with zero sum and no two consecutive declines, no adjacent equal elements, and no element more than one greater than the previous (random base sawtooth pattern).at n=33A200185
• Principal diagonal of the convolution array A213844.at n=15A213845
• Sigma(n)-n values in A085844.at n=26A216383
• Number of (n+1) X (3+1) 0..1 arrays with every 2 X 2 subblock having a single 1 or two 1s on the same edge.at n=5A251253
• Number of (n+1)X(6+1) 0..1 arrays with every 2X2 subblock having a single 1 or two 1s on the same edge.at n=2A251256
• T(n,k)=Number of (n+1)X(k+1) 0..1 arrays with every 2X2 subblock having a single 1 or two 1s on the same edge.at n=30A251258
• T(n,k)=Number of (n+1)X(k+1) 0..1 arrays with every 2X2 subblock having a single 1 or two 1s on the same edge.at n=33A251258
• Totients t such that the number of divisors of t equals the number of solutions of phi(x) = t.at n=20A305058
• Expansion of Product_{k=1..16} theta_3(q^k), where theta_3() is the Jacobi theta function.at n=33A320247
• a(n) = A330575(A025487(n)).at n=38A333962
• Number of partitions p of n such that max(p) == 1 mod 3.at n=43A373014