a(n) is the first pentagonal number that is nontrivially the sum of two pentagonal numbers of the type P(p) + P(p+n) (we always have P(k) = P(0) + P(k)).
A133312
a(n) is the first pentagonal number that is nontrivially the sum of two pentagonal numbers of the type P(p) + P(p+n) (we always have P(k) = P(0) + P(k)).
Terms
- a(0) =70a(1) =1926a(2) =6305a(3) =92a(4) =22632a(5) =34580a(6) =49051a(7) =66045a(8) =85562a(9) =1426a(10) =925a(11) =159251a(12) =188860a(13) =220992a(14) =255647a(15) =292825a(16) =852a(17) =2625a(18) =7107a(19) =466767a(20) =516560a(21) =568876a(22) =623715a(23) =681077a(24) =5192a(25) =803370a(26) =7957a(27) =935755a(28) =1005732a(29) =1078232
External references
- oeis: A133312