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A290963 Primes p such that sum of digits of p^3 is semiprime. 1
3, 7, 29, 41, 53, 59, 71, 83, 89, 113, 131, 137, 149, 157, 167, 173, 179, 197, 199, 227, 233, 239, 251, 263, 269, 281, 293, 317, 347, 379, 401, 409, 419, 431, 457, 463, 467, 479, 491, 503, 509, 521, 569, 617, 619, 641, 643, 647, 661, 677, 691, 701, 733, 743, 757, 761, 769, 797, 823, 829, 859, 883, 911 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

EXAMPLE

a(2) = 7 is prime: 7^3 = 343; 3 + 4 + 3 = 10 = 2*5 that is semiprime.

a(3) = 29 is prime : 29^3 = 24389; 2 + 4 + 3 + 8 + 9 = 26 = 2*13 that is semiprime.

a(5) = 53 is prime : 53^3 = 148877; 1 + 4 + 8 + 8 + 7 + 7 = 35 = 5*7 that is semiprime.

MAPLE

select(p -> isprime(p) and numtheory:-bigomega(convert(convert(p^3, base, 10), `+`)) = 2, [seq(i, i=3..1000, 2)]); # Robert Israel, Aug 15 2017

MATHEMATICA

Select[Prime[Range[500]], PrimeOmega[Plus @@ IntegerDigits[#^3]] == 2 &]

PROG

(PARI) lista(nn) = forprime(p=3, nn, if(bigomega(sumdigits(p^3)) == 2, print1(p, ", "))); \\ Altug Alkan, Aug 16 2017

CROSSREFS

Cf. A000040, A007605, A001358, A235398, A235399.

Sequence in context: A038900 A068485 A019352 * A261270 A171134 A080806

Adjacent sequences:  A290960 A290961 A290962 * A290964 A290965 A290966

KEYWORD

nonn,base

AUTHOR

K. D. Bajpai, Aug 15 2017

STATUS

approved

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Last modified October 15 05:43 EDT 2019. Contains 328026 sequences. (Running on oeis4.)