Nearest integer to cosh(n).

Terms

a(0) =1a(1) =2a(2) =4a(3) =10a(4) =27a(5) =74a(6) =202a(7) =548a(8) =1490a(9) =4052a(10) =11013a(11) =29937a(12) =81377a(13) =221207a(14) =601302a(15) =1634509a(16) =4443055a(17) =12077476a(18) =32829985a(19) =89241150a(20) =242582598a(21) =659407867a(22) =1792456423a(23) =4872401723a(24) =13244561065a(25) =36002449669a(26) =97864804714a(27) =266024120301a(28) =723128532146