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 A034959 Divide even numbers into groups with prime(n) elements and add together. 5
 2, 18, 70, 182, 484, 884, 1666, 2546, 4048, 6612, 8928, 13172, 17794, 22274, 28576, 37524, 48380, 57340, 71556, 85626, 98550, 118658, 138112, 163404, 196134, 224220, 249672, 281838, 310650, 347136, 420624, 467670, 525806, 571846, 655898 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Hieronymus Fischer, Table of n, a(n) for n = 1..10000 FORMULA From Hieronymus Fischer, Sep 27 2012: (Start) a(n) = 2*Sum_{k=(A007504(n-1)+1)..A007504(n)} (k-1), n > 1. a(n) = (A007504(n) - A007504(n-1))*(A007504(n) + A007504(n-1) - 1), n > 1. a(n) = 2*(A000217(A007504(n) - 1) - A000217(A007504(n-1) - 1)), n > 1. If we define A007504(0):=0, then the formulas above are also true for n=1. a(n) = 2*A034957(n). a(n) = A034960(n) - A000040(n). (End) EXAMPLE {0,2} #2 S=2; {4,6,8} #3 S=18; {10,12,14,16,18} #5 S=70; {20,22,24,26,28,30,32} #7 S=182. PROG (Python) from itertools import islice from sympy import nextprime def A034959_gen(): # generator of terms a, p = 0, 2 while True: yield p*((a<<1)+p-1) a, p = a+p, nextprime(p) A034959_list = list(islice(A034959_gen(), 20)) # Chai Wah Wu, Mar 22 2023 CROSSREFS Cf. A006003, A027441, A034960. Cf. A046992, A034956-A034958. Sequence in context: A112365 A242200 A258929 * A316902 A316904 A196812 Adjacent sequences: A034956 A034957 A034958 * A034960 A034961 A034962 KEYWORD nonn AUTHOR Patrick De Geest, Oct 15 1998 STATUS approved

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Last modified May 29 20:58 EDT 2023. Contains 363042 sequences. (Running on oeis4.)