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A014959 Integers n such that n divides 22^n - 1. 4

%I #11 Nov 17 2019 10:20:32

%S 1,3,7,9,21,27,39,49,63,81,117,147,189,243,273,343,351,441,507,567,

%T 729,819,1029,1053,1143,1323,1521,1701,1911,2187,2401,2457,2943,3081,

%U 3087,3159,3429,3549,3969,4401,4563,5103,5733,6561,6591,7203,7371

%N Integers n such that n divides 22^n - 1.

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

%H Max Alekseyev, <a href="/A014959/b014959.txt">Table of n, a(n) for n = 1..69065</a>

%t 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 *)

%Y 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).

%K nonn

%O 1,2

%A _Olivier GĂ©rard_

%E Edited by _Max Alekseyev_, Nov 16 2019

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Last modified March 28 09:04 EDT 2024. Contains 371240 sequences. (Running on oeis4.)