possible seq: Partial sum of A061712
Jonathan Post
jvospost3 at gmail.com
Tue Jul 1 19:58:15 CEST 2008
Partial sum of A061712 Smallest prime with Hamming weight n (i.e.
with exactly n 1's when written in binary).
2, 5, 12, 35, 66, 377, 504, 887, 1878, 3917, 7500, 13643, 21834,
95561, 159048, 288071, 419142, 941381, 1465668, 3431747, 7560514,
23811393, 38491456, 72037695, 139146046, 340210493, 600257340,
1136997179, 2210476858, 7545631545, 9693115192, 18274661175,
35186094902, 67398349621, 118937957172, 325079610163, 591367582514,
1622158684977, 2446792405808, 4643668177711
I'm interested in which values of the partial sum (beyond the first
two, a(8), a(10), and a(14)) are themselves prime. The sequence,
obviously, is strictly increasing, and alternates between even and
odd.
Example:
a(40) =
2 + 3 + 7 + 23 + 31 + 311 + 127 + 383 + 991 + 2039 + 3583 + 6143 +
8191 + 73727 + 63487+ 129023 + 131071+ 522239 + 524287+ 1966079 +
4128767 + 16250879 + 14680063 + 33546239 + 67108351 + 201064447 +
260046847 + 536739839 + 1073479679 + 5335154687 + 2147483647 +
8581545983 + 16911433727 + 32212254719 + 51539607551 + 206141652991 +
266287972351 + 1030791102463 + 824633720831 + 2196875771903 =
4643668177711 is prime.
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