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A114145
Self-describing sequence : 2 composite integers between two primes, then 4 composites, then 6, then 7, then 8, etc. The quantity of composites in each run is given by the sequence itself. (Sequence is strictly increasing and the smallest next available prime is used when needed).
0
2, 4, 6, 7, 8, 9, 10, 12, 13, 14, 15, 16, 18, 20, 21, 23, 24, 25, 26, 27, 28, 30, 32, 37, 38, 39, 40, 42, 44, 45, 46, 48, 53, 54, 55, 56, 57, 58, 60, 62, 63, 64, 67, 68, 69, 70, 72, 74, 75, 76, 77, 78, 80, 83, 84, 85, 86, 87, 88, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 102
OFFSET
2,1
EXAMPLE
Runs of composites between brackets:
2,(4,6),7,(8,9,10,12),13,(14,15,16,18,20,21),23,(24,25,26,27,28,30,32)...
.^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^
.2 comp. 4 comp. 6 comp. 7 comp. (etc.) = the sequence itself
PROG
(PARI) {m=20; k=2; v=[k]; for(j=1, m, count=0; while(count<v[j], if(!isprime(k), v=concat(v, k); count++); k++); k=nextprime(k); v=concat(v, k)); for(n=1, #v, print1(v[n], ", "))} \\ Klaus Brockhaus
CROSSREFS
Sequence in context: A015860 A147613 A155939 * A153351 A153343 A136499
KEYWORD
base,easy,nonn
AUTHOR
Eric Angelini, Feb 03 2006
STATUS
approved