|
| |
|
|
A258978
|
|
a(n) = 1 + sigma(n) + sigma(n)^2 + sigma(n)^3 + sigma(n)^4.
|
|
3
|
|
|
|
5, 121, 341, 2801, 1555, 22621, 4681, 54241, 30941, 111151, 22621, 637421, 41371, 346201, 346201, 954305, 111151, 2374321, 168421, 3187591, 1082401, 1727605, 346201, 13179661, 954305, 3187591, 2625641, 10013305, 837931, 27252361, 1082401, 16007041, 5421361
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
|
OFFSET
|
1,1
|
|
|
LINKS
|
Robert Price, Table of n, a(n) for n = 1..10000
OEIS Wiki, Cyclotomic Polynomials at x=n, n! and sigma(n)
|
|
|
FORMULA
|
a(n) = 1 + A000203(n) + A000203(n)^2 + A000203(n)^3 + A000203(n)^4.
a(n) = A053699(A000203(n)). - Michel Marcus, Jun 25 2015
|
|
|
MAPLE
|
with(numtheory): A258978:=n->1+sigma(n)+sigma(n)^2+sigma(n)^3+sigma(n)^4: seq(A258978(n), n=1..40); # Wesley Ivan Hurt, Jul 09 2015
|
|
|
MATHEMATICA
|
Table[1 + DivisorSigma[1, n] + DivisorSigma[1, n]^2 + DivisorSigma[1, n]^3 + DivisorSigma[1, n]^4, {n, 10000}]
Table[Cyclotomic[5, DivisorSigma[1, n]], {n, 10000}]
Total/@Table[DivisorSigma[1, n]^ex, {n, 40}, {ex, 0, 4}] (* Harvey P. Dale, Jun 24 2017 *)
|
|
|
PROG
|
(MAGMA) [(1 + DivisorSigma(1, n) + DivisorSigma(1, n)^2 + DivisorSigma(1, n)^3 + DivisorSigma(1, n)^4): n in [1..35]]; // Vincenzo Librandi, Jun 16 2015
(PARI) vector(50, n, polcyclo(6, sigma(n))) \\ Michel Marcus, Jun 25 2015
|
|
|
CROSSREFS
|
Cf. A000203 (sum of divisors of n).
Cf. A258979 (indices of primes in this sequence), A258980 (corresponding primes).
Sequence in context: A097993 A172806 A054752 * A128275 A028448 A108791
Adjacent sequences: A258975 A258976 A258977 * A258979 A258980 A258981
|
|
|
KEYWORD
|
easy,nonn
|
|
|
AUTHOR
|
Robert Price, Jun 15 2015
|
|
|
STATUS
|
approved
|
| |
|
|
