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A320704
Indices of primes followed by a gap (distance to next larger prime) of 12.
2
46, 47, 91, 97, 114, 121, 139, 168, 197, 203, 214, 232, 239, 240, 242, 267, 278, 280, 290, 312, 317, 342, 357, 363, 376, 381, 404, 423, 437, 439, 449, 452, 461, 470, 472, 489, 499, 511, 546, 550, 562, 565, 599, 600, 617, 633, 634, 647, 653, 657, 675, 680, 692, 698, 716, 728
OFFSET
1,1
COMMENTS
Indices of the primes given in A031930.
FORMULA
a(n) = A000720(A031930(n)).
A320704 = { i > 0 | prime(i+1) = prime(i) + 12 }.
MATHEMATICA
Select[Range[1000], Prime[#] + 12 == Prime[# + 1] &] (* Vincenzo Librandi, Mar 21 2019 *)
PROG
(PARI) A320704_vec(N=100, g=12, p=2, i=primepi(p)-1, L=List())={forprime(q=1+p, , i++; if(p+g==p=q, listput(L, i); N--||break)); Vec(L)} \\ returns the list of first N terms of the sequence
(Magma) [n: n in [1..1000] | NthPrime(n+1) - NthPrime(n) eq 12]; // Vincenzo Librandi, Mar 21 2019
CROSSREFS
Equals A000720 o A031930.
Row 6 of A174349.
Indices of 12's in A001223.
Cf. A029707, A029709, A320701, A320702, ..., A320720 (analog for gaps 2, 4, 6, 8, ..., 44), A116493 (gap 70), A116496 (gap 100), A116497 (gap 200), A116495 (gap 210).
Sequence in context: A165867 A058905 A345492 * A282465 A098194 A181460
KEYWORD
nonn
AUTHOR
M. F. Hasler, Oct 19 2018
STATUS
approved