This site is supported by donations to The OEIS Foundation.

 Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing. Other ways to donate

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A259184 a(n) = 1 - sigma(n) + sigma(n)^2. 3
 1, 7, 13, 43, 31, 133, 57, 211, 157, 307, 133, 757, 183, 553, 553, 931, 307, 1483, 381, 1723, 993, 1261, 553, 3541, 931, 1723, 1561, 3081, 871, 5113, 993, 3907, 2257, 2863, 2257, 8191, 1407, 3541, 3081, 8011, 1723, 9121, 1893, 6973, 6007, 5113, 2257, 15253 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Robert Price, Table of n, a(n) for n = 1..10000 FORMULA a(n) = 1 - A000203(n) + A000203(n)^2. a(n) = 1 - A000203(n) + A072861(n). - Omar E. Pol, Jun 20 2015 a(n) = A002061(A000203(n)). - Michel Marcus, Jun 25 2015 MAPLE with(numtheory): A259184:=n->1-sigma(n)+sigma(n)^2: seq(A259184(n), n=1..100); # Wesley Ivan Hurt, Jul 09 2015 MATHEMATICA Table[1 - DivisorSigma[1, n] + DivisorSigma[1, n]^2, {n, 10000}] Table[Cyclotomic[6, DivisorSigma[1, n]], {n, 10000}] PROG (PARI) a(n) = polcyclo(6, sigma(n)); \\ Michel Marcus, Jun 25 2015 CROSSREFS Cf. A000203 (sum of divisors of n). Cf. A259185 (indices of primes in this sequence), A259186 (corresponding primes). Sequence in context: A134854 A097444 A241718 * A259186 A151781 A224502 Adjacent sequences:  A259181 A259182 A259183 * A259185 A259186 A259187 KEYWORD easy,nonn AUTHOR Robert Price, Jun 20 2015 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified December 11 23:44 EST 2019. Contains 329945 sequences. (Running on oeis4.)