OFFSET
1,2
COMMENTS
Prime partial sums of prime numbers of measurement begin: 11, 23, 43, 73, 251, 347, 3343, 5639, 16937. The subsequence of squares begins: 1, 4, 3844 = 2^2 * 31^2.
LINKS
Chai Wah Wu, Table of n, a(n) for n = 1..10000
FORMULA
a(n) = Sum_{i=1..n} A002049(i).
EXAMPLE
a(10) = 1 + 3 + 7 + 12 + 20 + 30 + 44 + 59 + 75 + 96 = 347 is prime.
PROG
(Python)
from itertools import count, accumulate, islice
from collections import deque
def A173702_gen(): # generator of terms
aset, alist, a, b = set(), deque(), 0, 0
for k in count(1):
if k in aset:
aset.remove(k)
else:
a += k
yield (b:=a+b)
aset |= set(k+d for d in accumulate(alist))
alist.appendleft(k)
CROSSREFS
KEYWORD
nonn
AUTHOR
Jonathan Vos Post, Nov 25 2010
STATUS
approved
