a(n) is the sigma irregularity of the n-th power of a path graph of length at least 3*n.

Terms

a(0) =2a(1) =14a(2) =52a(3) =140a(4) =310a(5) =602a(6) =1064a(7) =1752a(8) =2730a(9) =4070a(10) =5852a(11) =8164a(12) =11102a(13) =14770a(14) =19280a(15) =24752a(16) =31314a(17) =39102a(18) =48260a(19) =58940a(20) =71302a(21) =85514a(22) =101752a(23) =120200a(24) =141050a(25) =164502a(26) =190764a(27) =220052a(28) =252590a(29) =288610