A319746 - OEIS

%I #9 Sep 28 2018 22:37:27

%S 12,18,32,35,43,59,142,187,241,265,610,778,1521,2163,2625,3267,3729,

%T 9242,15905,16725,18852,56207,63265,87538,94596,333718,780890,839383,

%U 959394,1114534,1745662,2198585,2424613,2815415,5501438,7371962,9717796,21010738,27800086,31173396

%N Quasi-Repfigit numbers (or Quasi-Keith numbers)

%C Numbers n>9 with following property: form a sequence b(i) whose initial terms are the t digits of n, later terms given by rule that b(i) = sum of t previous terms; then n - 1 or n + 1 appears in the sequence.

%e a(1) = 12 because 1 + 2 = 3, 2 + 3 = 5, 3 + 5 = 8, 5 + 8 = 13 = 12 + 1.

%e a(2) = 18 because 1 + 8 = 9, 8 + 9 = 17 = 18 - 1.

%p P:=proc(q) local b, k,n,v; for n from 1 to q do b:=ilog10(n)+1;

%p if b>1 then v:=[]; for k from 1 to b do

%p v:=[op(v),trunc(n/10^(b-k)) mod 10]; od; v:=[op(v),add(v[k],k=1..b)];

%p while v[nops(v)]<n-1 do v:=[op(v),add(v[k], k=nops(v)-b+1..nops(v))]; od;

%p if v[nops(v)]=n-1 or v[nops(v)]=n+1 then print(n); fi; fi; od; end: P(10^7);

%Y Cf. A007629, A130010.

%K nonn,base

%O 1,1

%A _Paolo P. Lava_, Sep 27 2018