A165742 First differences of A003591.
1, 2, 3, 1, 6, 2, 12, 4, 17, 7, 8, 34, 14, 16, 68, 28, 32, 87, 49, 56, 64, 174, 98, 112, 128, 348, 196, 224, 256, 353, 343, 392, 448, 512, 706, 686, 784, 896, 1024, 1412, 1372, 1568, 1792, 2048, 423, 2401, 2744, 3136, 3584, 4096, 846, 4802, 5488, 6272, 7168, 8192, 1692, 9604, 10976, 12544, 14336, 2961, 13423, 3384, 19208
Offset: 1
Keywords
Examples
For n = 5, the 5th number of the form 2^i*7^j with i, j >= 0 is 8, and the 6th number of the form 2^i*7^j with i, j >= 0 is 14, so the difference is 14 - 8 = 6.
Links
- Charles R Greathouse IV, Table of n, a(n) for n = 1..10000
Programs
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PARI
diff(v)=vector(#v-1,i,v[i+1]-v[i]) list(lim)=my(v=List(),N);for(n=0,log(lim)\log(7),N=7^n;while(N<=lim,listput(v,N);N<<=1));diff(vecsort(Vec(v))) \\ Charles R Greathouse IV, Jun 28 2011
Comments