A152622 Tetrahedral numbers n*(n+1)*(n+2)/6 with n, n+1 and n+2 nonprime.

120, 560, 1540, 2600, 2925, 3276, 5984, 6545, 7140, 9880, 15180, 19600, 20825, 22100, 27720, 29260, 30856, 41664, 43680, 45760, 54740, 70300, 73150, 76076, 88560, 102340, 105995, 109736, 125580, 129766, 134044, 138415, 142880, 161700

Offset: 1

Author

Juri-Stepan Gerasimov, Dec 10 2008

Keywords

• nonn
• easy

Crossrefs

Cf. A000292, A141468, A144291.

Programs

Maple

tet := proc(n) n*(n+1)*(n+2)/6 ; end: for n from 1 to 300 do if not isprime(n) and not isprime(n+1) and not isprime(n+2) then printf("%d,",tet(n)) ; fi; od: # R. J. Mathar, Dec 10 2008

PARI

p=7;forprime(q=11,1e2,for(n=p+1,q-3,print1(binomial(n+2,3)", "));p=q) \\ Charles R Greathouse IV, Dec 21 2011

Extensions

20400 replaced by 19600, 20625 replaced by 20825, R. J. Mathar, Dec 10 2008