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A014959 Integers n such that n divides 22^n - 1. 4
1, 3, 7, 9, 21, 27, 39, 49, 63, 81, 117, 147, 189, 243, 273, 343, 351, 441, 507, 567, 729, 819, 1029, 1053, 1143, 1323, 1521, 1701, 1911, 2187, 2401, 2457, 2943, 3081, 3087, 3159, 3429, 3549, 3969, 4401, 4563, 5103, 5733, 6561, 6591, 7203, 7371 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Also, numbers n such that n divides s(n), where s(1)=1, s(k)=s(k-1)+k*22^(k-1) (cf. A014940).

LINKS

Max Alekseyev, Table of n, a(n) for n = 1..69065

MATHEMATICA

nxt[{n_, s_}]:={n+1, s+(n+1)*22^n}; Transpose[Select[NestList[nxt, {1, 1}, 7500], Divisible[ Last[#], First[#]]&]][[1]] (* Harvey P. Dale, Jan 27 2015 *)

CROSSREFS

Integers n such that n divides b^n - 1: A067945 (b=3), A014945 (b=4), A067946 (b=5), A014946 (b=6), A067947 (b=7), A014949 (b=8), A068382 (b=9), A014950 (b=10), A068383 (b=11), A014951 (b=12), A116621 (b=13), A014956 (b=14), A177805 (b=15), A014957 (b=16), A177807 (b=17), A128358 (b=18), A125000 (b=19), A128360 (b=20), A014960 (b=24).

Sequence in context: A045797 A118555 A056652 * A057233 A125227 A057286

Adjacent sequences:  A014956 A014957 A014958 * A014960 A014961 A014962

KEYWORD

nonn

AUTHOR

Olivier Gérard

EXTENSIONS

Edited by Max Alekseyev, Nov 16 2019

STATUS

approved

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Last modified February 18 02:57 EST 2020. Contains 332006 sequences. (Running on oeis4.)