A034961 Sums of three consecutive primes.
10, 15, 23, 31, 41, 49, 59, 71, 83, 97, 109, 121, 131, 143, 159, 173, 187, 199, 211, 223, 235, 251, 269, 287, 301, 311, 319, 329, 349, 371, 395, 407, 425, 439, 457, 471, 487, 503, 519, 533, 551, 565, 581, 589, 607, 633, 661, 679, 689, 701, 713, 731, 749, 771
Offset: 1
Examples
a(1) = 10 = 2 + 3 + 5. a(42) = 565 = 181 + 191 + 193.
Links
- Zak Seidov, Table of n, a(n) for n = 1..1000
- Carlos Rivera, Puzzle 1021. p(k)+p(k+1)+1, The Prime Puzzles and Problems Connection.
Programs
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Magma
[&+[ NthPrime(n+k): k in [0..2] ]: n in [1..50] ]; // Vincenzo Librandi, Apr 03 2011
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Mathematica
Plus @@@ Partition[ Prime[ Range[60]], 3, 1] (* Robert G. Wilson v, Feb 11 2005 *) 3 MovingAverage[Prime[Range[60]], {1, 1, 1}] (* Jean-François Alcover, Nov 12 2018 *)
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PARI
a(n)=my(p=prime(n),q=nextprime(p+1)); p+q+nextprime(q+1) \\ Charles R Greathouse IV, Jul 01 2013
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PARI
is(n)=my(p=precprime(n\3),q=nextprime(n\3+1),r=n-p-q); if(r>q, r==nextprime(q+2), r==precprime(p-1) && r) \\ Charles R Greathouse IV, Jul 05 2017
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Python
from sympy import nextprime from itertools import count, islice def agen(): # generator of terms p, q, r = 2, 3, 5 while True: yield p + q + r p, q, r = q, r, nextprime(r) print(list(islice(agen(), 54))) # Michael S. Branicky, Dec 27 2022
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Sage
BB = primes_first_n(57) L = [] for i in range(55): L.append(BB[i]+BB[i+1]+BB[i+2]) L # Zerinvary Lajos, May 14 2007
Formula
a(n) = Sum_{k=0..2} A000040(n+k). - Omar E. Pol, Feb 28 2020
Comments