A373172 - OEIS

A373172

a(1) = 1; for n >= 2, a(n) = noz(a(n-1) + 4*n - 3), where noz(n) = A004719(n).

1, 6, 15, 28, 45, 66, 91, 12, 45, 82, 123, 168, 217, 27, 84, 145, 21, 9, 82, 159, 24, 19, 18, 111, 28, 129, 234, 343, 456, 573, 694, 819, 948, 181, 318, 459, 64, 213, 366, 523, 684, 849, 118, 291, 468, 649, 834, 123, 316, 513, 714, 919, 1128, 1341, 1558, 1779

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

COMMENTS

Zeroless analog of the positive hexagonal numbers.

LINKS

Paolo Xausa, Table of n, a(n) for n = 1..10000

MATHEMATICA

noz[n_] := FromDigits[DeleteCases[IntegerDigits[n], 0]];

Block[{n = 1}, NestList[noz[++n*4 - 3 + #] &, 1, 100]]

nxt[{n_, a_}]:={n+1, FromDigits[DeleteCases[IntegerDigits[a+4n+1], 0]]}; NestList[nxt, {1, 1}, 60][[;; , 2]] (* Harvey P. Dale, Jul 08 2024 *)

PROG