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A034960
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Divide odd numbers into groups with prime(n) elements and add together.
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7
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4, 21, 75, 189, 495, 897, 1683, 2565, 4071, 6641, 8959, 13209, 17835, 22317, 28623, 37577, 48439, 57401, 71623, 85697, 98623, 118737, 138195, 163493, 196231, 224321, 249775, 281945, 310759, 347249, 420751, 467801, 525943, 571985, 656047
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OFFSET
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1,1
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LINKS
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FORMULA
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EXAMPLE
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{1,3} #2 S=4;
{5,7,9} #3 S=21;
{11,13,15,17,19} #5 S=75;
{21,23,25,27,29,31,33} #7 S=189.
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MAPLE
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S:= n-> sum(ithprime(k), k=1..n): seq(S(n+1)^2-S(n)^2, n=0..40); # Gary Detlefs, Dec 20 2011
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PROG
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(Python)
from itertools import islice
from sympy import nextprime
def A034960_gen(): # generator of terms
a, p = 0, 2
while True:
yield p*((a<<1)+p)
a, p = a+p, nextprime(p)
(PARI) a0(n) = vecsum(primes(n))^2 - vecsum(primes(n-1))^2; \\ Michel Marcus, Jun 16 2024
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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