A036331 Composite numbers n such that juxtaposition of prime factors of n has length 7.

128, 192, 288, 320, 352, 416, 432, 448, 480, 528, 544, 608, 624, 648, 672, 720, 736, 792, 800, 816, 880, 912, 928, 936, 968, 972, 992, 1008, 1040, 1080, 1104, 1120, 1144, 1184, 1188, 1200, 1224, 1232, 1312, 1320, 1352, 1360, 1368, 1376, 1392, 1404, 1452

Offset: 1

Author

Patrick De Geest, Dec 15 1998

Keywords

• nonn
• base
• fini
• easy

Comments

The last term of this sequence is a(919196)=9943081.

Links

• Nathaniel Johnston, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A036326-A036334.

Programs

Maple

isA036331 := proc(n) local d: d:=ifactors(n)[2]: return `if`(not isprime(n) and add(length(d[j][1])*d[j][2], j=1..nops(d))=7, n, NULL): end: seq(isA036331(n),n=2..1452); # Nathaniel Johnston, Jun 22 2011