A067867 Numbers n such that n and 2^n end with the same 4 digits.
8736, 18736, 28736, 38736, 48736, 58736, 68736, 78736, 88736, 98736, 108736, 118736, 128736, 138736, 148736, 158736, 168736, 178736, 188736, 198736, 208736, 218736, 228736, 238736, 248736, 258736, 268736, 278736, 288736, 298736, 308736
Offset: 1
Links
- Tanya Khovanova, Recursive Sequences
- Index entries for linear recurrences with constant coefficients, signature (2,-1).
Programs
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PARI
isok(n) = (2^n - n) % 10000 == 0; \\ Michel Marcus, Nov 23 2013
Formula
a(n) = 8736 + 10^4(n-1).
a(n) = 2*a(n-1)-a(n-2). G.f.: 16*x*(546+79*x)/(1-x)^2. [Colin Barker, Dec 01 2012]