1,1

The next term is of order 10^17, since the next constraint is A154328(27) = 10^19 = sum of the first 10^19 digits of A154328. Even if from term 500 on there were 30 digits "9" in each term, their sum would stay below 10^19 for more than 3*10^16 terms. But at index 498+10^12, the value of 10^31 is reached and among the next 10^17 terms, about half of the digits will be zero.

a(1)=2 since the first jump of A154328 occurs at index 2, where the value raises to A154328[2]=10 > A154328[1]+1=2.

a(2)=5 since the 2nd jump of A154328 occurs at index 5, where the value raises to A154328[5]=20 > A154328[4]+1=13.

(PARI) A154328={concat([[1, 10, 11, 12, 20, 111, 112, 120], vector(16+1, i, -1+1000+i), 10000, 10^19, vector(42+1, i, -1+10^19+10^11*8+i), 10^19+4*10^18-1, 10^20-10^11+(10^11-1)/9, vector(413+1, i, -1+(10^21-10^16)/9+i), (10^21-10^16)/9+3*10^15-1, vector(10, i, 10^(20+i)-1), 10^31-10^12 /* +i=0..10^17 */])};

for( i=2, #A154328, A154328[i] > A154328[i-1]+1 & print1(i", "))

A154330(n) = A154328(a(n)).

Sequence in context: A047325 A102611 A057915 this_sequence A087943 A034020 A121411

Adjacent sequences: A154326 A154327 A154328 this_sequence A154330 A154331 A154332

base,nonn

M. F. Hasler (MHasler(AT)univ-ag.fr), Jan 13 2009