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A087884 a(n) = PrimePi[PrimePi[n-1]] + Prime[Abs[n - Prime[n-1]]] 0
3, 4, 13, 15, 25, 31, 43, 63, 70, 92, 106, 110, 130, 154, 183, 185, 215, 233, 237, 267, 281, 315, 357, 377, 383, 401, 405, 425, 504, 526, 568, 574, 622, 624, 658, 688, 714, 748, 779, 793, 859, 863, 883, 887, 973, 1039, 1057, 1067, 1093, 1115, 1123, 1199 (list; graph; refs; listen; history; text; internal format)
OFFSET

4,1

COMMENTS

A prime based reinversion sequence based on the A004001 pattern.

LINKS

Table of n, a(n) for n=4..55.

MATHEMATICA

prid[n_Integer?Positive] := prid[n] =PrimePi[PrimePi[n-1]] + Prime[Abs[n - Prime[n-1]]] prid[1] = prid[2] = 1 digits=256 a=Table[prid[n], {n, 4, digits+4}]

CROSSREFS

Cf. A004001.

Sequence in context: A208847 A278426 A293280 * A057570 A024853 A023857

Adjacent sequences:  A087881 A087882 A087883 * A087885 A087886 A087887

KEYWORD

nonn

AUTHOR

Roger L. Bagula, Oct 12 2003

STATUS

approved

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Last modified January 22 12:13 EST 2019. Contains 319363 sequences. (Running on oeis4.)