A373824 Sorted positions of first appearances in the run-lengths (differing by 0) of the run-lengths (differing by 2) of the odd primes.
1, 2, 11, 13, 29, 33, 45, 51, 57, 59, 69, 75, 105, 129, 211, 227, 301, 313, 321, 341, 407, 413, 447, 459, 537, 679, 709, 767, 1113, 1301, 1405, 1411, 1429, 1439, 1709, 1829, 1923, 2491, 2543, 2791, 2865, 3301, 3471, 3641, 4199, 4611, 5181, 5231, 6345, 6555
Offset: 1
Keywords
Examples
The runs of odd primes differing by 2 begin: 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79 with lengths: 3, 2, 2, 1, 2, 1, 2, 1, 1, 2, 1, 2, 1, 1, 1, 1, 2, 2, 1, 1, 1, 2, 2, 1, 1, 1, 1, 2, 2, 2, ... which have runs beginning: 3 2 2 1 2 1 2 1 1 2 1 2 1 1 1 1 2 2 1 1 1 with lengths: 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 4, 2, 3, 2, 4, 3,... with sorted positions of first appearances a(n).
Crossrefs
The unsorted version is A373825.
A000040 lists the primes.
A001223 gives differences of consecutive primes (firsts A073051), run-lengths A333254 (firsts A335406), run-lengths of run-lengths A373821.
A046933 counts composite numbers between primes.
A065855 counts composite numbers up to n.
A071148 gives partial sums of odd primes.
Programs
-
Mathematica
t=Length/@Split[Length/@Split[Select[Range[3,10000],PrimeQ],#1+2==#2&]]; Select[Range[Length[t]],FreeQ[Take[t,#-1],t[[#]]]&]
Comments