A290264 Initial primes of 9 consecutive primes with 8 consecutive gaps 16, 14, 12, 10, 8, 6, 4, 2.

32465047, 37091581, 146742847, 239659891, 245333251, 272213797, 1060690651, 1541736811, 2002738207, 2480351677, 2636566351, 4421955007, 6168859201, 8158683037, 10367633527, 10623394321, 11452116817, 11691059641, 11892876841, 13551877831, 15043908637

Offset

1,1

Comments

All terms = {1,7} mod 30.

For initial primes of 7 consecutive primes with 6 consecutive gaps 12, 10, 8, 6, 4, 2 and 8 consecutive primes with 7 consecutive gaps 14, 12, 10, 8, 6, 4, 2 see A290161 and A290162 respectively.

a(6) > 250000000.

Links

Table of n, a(n) for n=1..21.

Example

32465047 is a member of this sequence because the 9 consecutive primes 32465047, 32465063, 32465077, 32465089, 32465099, 32465107, 32465113, 32465117, 32465119 have consecutive gaps 16, 14, 12, 10, 8, 6, 4, 2. That is, 32465047 + 16 = 32465063, 32465063 + 14 = 32465077, 32465077 + 12 = 32465089, 32465089 + 10 = 32465099, 32465099 + 8 = 32465107, 32465107 + 6 = 32465113, 32465113 + 4 = 32465117, 32465117 + 2 = 32465119.

Prog

(GAP)
P:=Filtered([1..50000000], IsPrime);; I:=Reversed([2, 4, 6, 8, 10, 12, 14, 16]);;
P1:=List([1..Length(P)-1], i->P[i+1]-P[i]);;  Collected(last);;
P2:=List([1..Length(P)-Length(I)], i->[P1[i], P1[i+1], P1[i+2], P1[i+3], P1[i+4], P1[i+5], P1[i+6], P1[i+7]]);;
P3:=List(Positions(P2, I), i->P[i]); Length(P3);

Crossrefs

Cf. A078847, A190814, A190817, A190819, A190838, A290161, A290162.

Sequence in context: A252356 A153752 A209912 * A206043 A157080 A157081

Adjacent sequences: A290261 A290262 A290263 * A290265 A290266 A290267

Keyword

nonn

Author

Muniru A Asiru, Jul 25 2017

Extensions

a(6)-a(21) from Giovanni Resta, Jul 25 2017

Status

approved