130320

Appears in sequences

• a(n) = Sum_{d|n, n/d=1 mod 4} d^4 - Sum_{d|n, n/d=3 mod 4} d^4.at n=18A050468
• Values of n^2 - 1 resulting from A050795.at n=26A050799
• Jordan function J_4(n).at n=18A059377
• Positive numbers which are one less than a perfect square that is also another power.at n=25A062965
• A level 11 weight 5 form.at n=18A065103
• a(1) = 1, a(n) = a(n-1)*n if n is composite, a(n) = a(n-1) + n if n is a prime.at n=9A083525
• a(n) is the difference between the largest and smallest integer solutions to n=x/pi(x), where pi(x) = A000720(x).at n=43A087236
• a(n) = n^4 - 1.at n=18A123865
• Number of reduced 3 X 3 semimagic squares with distinct nonnegative integer entries and maximum entry n.at n=25A173727
• a(n) = (-1)^n * Sum_{2*m + 1 | 2*n + 1} (-1)^m (2*m + 1)^4.at n=9A204342
• a(n) = n^4 * Sum_{d|n} (-1)^(n/d + 1) * mu(d) / d^4.at n=18A338549
• Even positive numbers that are one less than the square of a perfect power.at n=12A389955