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 A351775 Value of all prime numbers p after applying the rule: sigma_n( sigma_n-1( ... sigma_3( sigma_2( sigma_1( sigma_0(p) )))...)) (from sigma_0 up to sigma_n), where sigma_k(m) is the sum of the k-th powers of the divisors of m and p is prime (the choice of the prime p is arbitrary). 0
 2, 3, 10, 1134, 1779741927370, 18420061471485119632756156593998809036909505674991629417779936 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 COMMENTS a(6) has 368 digits. LINKS Table of n, a(n) for n=0..5. FORMULA a(n) = sigma_n( a(n-1) ) for n >= 1, a(0) = 2. EXAMPLE a(0) = sigma_0(2) = 2, a(1) = sigma_1( sigma_0(2) ) = 3, a(2) = sigma_2( sigma_1( sigma_0(2) )) = sigma_2(3) = 10, a(3) = sigma_3( sigma_2( sigma_1( sigma_0(2) ))) = sigma_3(10) = 1134. ... MATHEMATICA a[0] = 2; a[n_] := a[n] = DivisorSigma[n, a[n - 1]]; Table[a[n], {n, 0, 6}] CROSSREFS Cf. A070239. Sequence in context: A184163 A218271 A128125 * A070239 A002443 A111788 Adjacent sequences: A351772 A351773 A351774 * A351776 A351777 A351778 KEYWORD nonn AUTHOR Wesley Ivan Hurt, Feb 18 2022 STATUS approved

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Last modified May 21 11:30 EDT 2024. Contains 372736 sequences. (Running on oeis4.)