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A152819 "Upper primes" (see A152754). 2
2, 11, 37, 41, 43, 47, 59, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 227, 229, 233, 239, 251, 521, 523, 541, 547, 557, 563, 569, 571, 577, 587, 593, 599, 601, 607, 613, 617, 619, 631, 641, 643, 647, 653, 659, 661, 673, 677, 683, 691, 701, 709, 719, 727 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..2490

MATHEMATICA

fh[n_, h_] := If[h==1, Mod[n, 2], If[Mod[n, 4]>=2, 1, 0]]; half[n_, h_ ] := Module[{t=1, s=0, m=n}, While[m>0, s += fh[m, h]*t; m=Quotient[m, 4]; t *= 2]; s]; mb[n_] := FromDigits[Riffle[IntegerDigits[n, 2], 0], 2]; aQ[n_] := PrimeQ[n] && mb[half[ n, 1]] < mb[half[n, 2]]; Select[Range[730], aQ] (* Amiram Eldar, Dec 16 2018 from the PARI code *)

PROG

(PARI) a000695(n) = fromdigits(binary(n), 4);

half1(n) = { my(t=1, s=0); while(n>0, s += (n%2)*t; n \= 4; t *= 2); (s); }; \\ A059905

half2(n) = { my(t=1, s=0); while(n>0, s += ((n%4)>=2)*t; n \= 4; t *= 2); (s); }; \\ A059906

isok(n) = isprime(n) && a000695(half1(n)) < a000695(half2(n)); \\ Michel Marcus, Dec 15 2018

CROSSREFS

Cf. A152754.

Sequence in context: A096977 A084098 A263547 * A297406 A178138 A220888

Adjacent sequences:  A152816 A152817 A152818 * A152820 A152821 A152822

KEYWORD

nonn

AUTHOR

Vladimir Shevelev, Dec 13 2008

EXTENSIONS

More terms from Michel Marcus, Dec 15 2018

STATUS

approved

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Last modified April 16 18:53 EDT 2021. Contains 343050 sequences. (Running on oeis4.)