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A087874
a[n] =PrimePi[PrimePi[n-1]] + a[n - a[n-1]]
0
1, 1, 1, 2, 2, 4, 3, 4, 4, 6, 4, 7, 7, 6, 7, 7, 9, 8, 8, 11, 10, 11, 11, 11, 10, 11, 11, 13, 11, 12, 12, 16, 14, 16, 13, 16, 15, 16, 16, 16, 15, 17, 17, 17, 19, 17, 18, 18, 18, 22, 17, 19, 22, 22, 20, 22, 19, 22, 21, 23, 23, 23, 23, 22, 24, 24, 24, 25, 25, 27, 25, 26, 26, 26, 26, 30
OFFSET
1,4
COMMENTS
A reinversion type sequence using the distribution sequence of the primes as the inverse function and A004001 as the pattern function.
Frequency count shows this sequence doesn't cover the integer domain.
MATHEMATICA
crid[n_Integer?Positive] := crid[n] =PrimePi[PrimePi[n-1]] + crid[n - crid[n-1]] crid[1] = crid[2] = 1 digits=256 a=Table[crid[n], {n, 1, digits}]
CROSSREFS
Cf. A004001.
Sequence in context: A217754 A319397 A094950 * A363341 A166267 A117484
KEYWORD
nonn
AUTHOR
Roger L. Bagula, Oct 11 2003
STATUS
approved