A207890 a(0)=1; for n>=1,- the minimal increasing sequence, such that, for n>=1, the row sums of Pascal-like triangle with left side {1,1,1,...} and right side {a(0), a(1), a(2),...} form an increasing sequence of primes.

1, 1, 2, 3, 4, 5, 8, 11, 14, 17, 20, 29, 44, 55, 66, 69, 72, 77, 86, 149, 152, 167, 172, 183, 198, 229, 230, 233, 254, 267, 276, 285, 316, 355, 370, 377, 402, 423, 458, 469, 478, 517, 570, 623, 704, 725, 730, 753, 762, 801, 818, 839, 858, 861, 938, 943, 982

Offset

0,3

Links

Table of n, a(n) for n=0..56.

Example

Triangle begins
n/k.|..0.....1.....2.....3.....4.....5.....6.....7
==================================================
.0..|..1
.1..|..1.....1
.2..|..1.....2.....2
.3..|..1.....3.....4.....3
.4..|..1.....4.....7.....7.....4
.5..|..1.....5....11....14....11.....5
.6..|..1.....6....16....25....25....16.....8
.7..|..1.....7....22....41....50....41....24.....11
.8..|
The row sums for n >= 1 form sequence A055496.

Mathematica

rows={{1}, {1, 1}}; Table[(x=Flatten[{1, 2 MovingAverage[rows[[n]], 2]}]; sx=Apply[Plus, x]; z=NextPrime[sx, NestWhile[#+1&, 1, NextPrime[sx, #]-sx<Last[rows[[n]]]&]]-sx; rows=Append[rows, Append[x, z]]), {n, 2, 100}]; A207890=Map[Last[#]&, rows]

Crossrefs

Cf. A055496.

Sequence in context: A343608 A144679 A309679 * A008825 A261629 A244395

Adjacent sequences: A207887 A207888 A207889 * A207891 A207892 A207893

Keyword

nonn,tabl

Author

Vladimir Shevelev and Peter J. C. Moses, Feb 21 2012

Status

approved