The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A305718 a(n) is the smallest number k such that sigma(k + 2n) = sigma(k) - 2n, or -1 if no such number exists. 0
 1, 6976, 15, 35, 39, 51, 95, 831, 45, 88, 63, 222, 135, 37888, 96, 284, 117, 354, 175, 84, 153, 176, 3893, 267, 210 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS Even-indexed terms of A304994. If it exists, a(25) > 10^9.  Other large (if existent) terms include a(55), a(73), and a(97). Terms a(26)..a(54) are 120, 160, 228, 339, 602, 156, 1393, 425, 279, 1204, 462, 70912, 231, 488, 633, 1099, 575, 228, 369, 1211, 387, 364, 605, 579, 396, 725, 1731, 1146, 455. a(25) > 10^12, if it exists. - Giovanni Resta, Jun 10 2018 LINKS FORMULA a(n) = A304994(2n). CROSSREFS Cf. A304994. Sequence in context: A234111 A184228 A050225 * A237237 A251651 A050673 Adjacent sequences:  A305715 A305716 A305717 * A305719 A305720 A305721 KEYWORD nonn,more AUTHOR Jon E. Schoenfield, Jun 08 2018 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 September 18 17:02 EDT 2020. Contains 337170 sequences. (Running on oeis4.)