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A116534 Start with 1 and 2; if number is even join with last number and divide by 2, if it is odd add 1 and divide by 2. 1

%I

%S 1,2,6,13,7,4,37,19,10,955,478,477739,238870,238869619435,

%T 119434809718,119434809717559717404859,59717404858779858702430,

%U 5971740485877985870242979858702429389929351215

%N Start with 1 and 2; if number is even join with last number and divide by 2, if it is odd add 1 and divide by 2.

%C Rapidly growing: for n=10,20,30,40,50 the terms have 3, 138, 914, 3649, 248128 digits respectively (cf. A131059). - _Hieronymus Fischer_, Jun 12 2007

%F 1,2 = 12 / 2 = 6, is even so = 26 /2 = 13 is odd so sum 1 and / by 2 = 7, +1 /2 = 4, is even so I join with 7 = 74 /2 = 37 +1 /2 = 19, etc

%F a(n)=ceiling(a(n-1)/2)+(1+(-1)^a(n-1))*10^floor(log_10(a(n-1))+1)*a(n-2)/4, n>=2. - _Hieronymus Fischer_, Jun 12 2007

%Y Cf. A131059.

%K nonn

%O 0,2

%A _Rodolfo Kurchan_, Mar 26 2006

%E More terms from _Hieronymus Fischer_, Jun 12 2007

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Last modified October 18 02:23 EDT 2019. Contains 328135 sequences. (Running on oeis4.)