%I A053716
%S A053716 7,127,1093,5461,19531,55987,137257,299593,597871,1111111,1948717,
%T A053716 3257437,5229043,8108731,12204241,17895697,25646167,36012943,49659541,
%U A053716 67368421,90054427,118778947,154764793,199411801,254313151,321272407
%N A053716 a(n) = 1111111 in base n.
%C A053716 Let Phi_k(x) be the k-th cyclotomic polynomial and form the sequence 
               Phi_k(0), Phi_k(1), Phi_k(2), ... This gives A000027 (k=2), A002061 
               (k=3), A002522 (k=4), A053699 (k=5), A002061 (k=6), A053716 (k=7), 
               A002523 (k=8), A060883 (k=9), A060884 (k=10), A060885 (k=11), A060886 
               (k=12), A060887 (k=13), A060888 (k=14), A060889 (k=15), A060890 (k=16), 
               A060891 (k=18), A060892 (k=20), A060893 (k=24), A060894 (k=30), A060895 
               (k=32), A060896 (k=36).
%F A053716 a(n) =n^6+n^5+n^4+n^3+n^2+n+1 =(n^7-1)/(n-1)
%e A053716 a(3)=1093 because 1111111 base 3 =729+243+81+27+9+3+1=121
%Y A053716 Sequence in context: A084940 A139987 A061744 this_sequence A088550 A064754 
               A025166
%Y A053716 Adjacent sequences: A053713 A053714 A053715 this_sequence A053717 A053718 
               A053719
%K A053716 base,nonn
%O A053716 1,1
%A A053716 Henry Bottomley (se16(AT)btinternet.com), Mar 23 2000