A074864 a(n) = a(n-1) + a(n-2) + R(a(n-3)) + R(a(n-4)) where a(1)=a(2)=a(3)=a(4)=1 and R(n) (A004086) is the reverse of n.
1, 1, 1, 1, 4, 7, 13, 25, 49, 112, 244, 502, 1051, 2206, 3904, 7816, 19243, 37174, 66697, 144349, 292510, 563698, 1879315, 3401746, 6192718, 15630610, 33434152, 63708721, 106919440, 197375245, 342218854, 597294436, 1527006682, 3125687152
Offset: 1
Links
- Harvey P. Dale, Table of n, a(n) for n = 1..1000
Programs
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Mathematica
RecurrenceTable[{a[1]==a[2]==a[3]==a[4]==1, a[n]==a[n-1]+a[n-2]+ IntegerReverse[ a[n-3]]+IntegerReverse[a[n-4]]},a,{n,40}] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Oct 10 2017 *)
Extensions
More terms from Joshua Zucker, May 08 2006
Definition adapted to offset by Georg Fischer, Jun 18 2021