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 A224903 a(n) = sigma(2*n^4) - sigma(n^4). 2
 2, 32, 242, 512, 1562, 3872, 5602, 8192, 19682, 24992, 32210, 61952, 61882, 89632, 189002, 131072, 177482, 314912, 275122, 399872, 677842, 515360, 585122, 991232, 976562, 990112, 1594322, 1434112, 1465082, 3024032, 1908610, 2097152, 3897410, 2839712, 4375162, 5038592, 3852442 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Here sigma(n) = A000203(n), the sum of the divisors of n. LINKS FORMULA a(n) = A054785(n^4). Logarithmic derivative of A224902. EXAMPLE L.g.f.: L(x) = 2*x + 32*x^2/2 + 242*x^3/3 + 512*x^4/4 + 1562*x^5/5 +... where exponentiation yields the g.f. of A224902: exp(L(x)) = 1 + 2*x + 18*x^2 + 114*x^3 + 450*x^4 + 2298*x^5 +... PROG (PARI) {a(n)=sigma(2*n^4)-sigma(n^4)} for(n=1, 30, print1(a(n), ", ")) CROSSREFS Cf. A224902, A054785, A000203. Sequence in context: A053316 A053053 A053054 * A008512 A179074 A035602 Adjacent sequences:  A224900 A224901 A224902 * A224904 A224905 A224906 KEYWORD nonn AUTHOR Paul D. Hanna, Jul 24 2013 STATUS approved

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Last modified January 28 21:00 EST 2022. Contains 350663 sequences. (Running on oeis4.)